8th DIAGNOSTIC TEST

8^th DIAGNOSTIC TEST

Part A

Direction : Each of the questions or incomplete

Statements below is followed by five suggestion

Answers or completions.Choose the one that is best in each case and then blacken the corresponding space on the answer sheet.

1.Niacin will most likely be found in foods containing vitamin.

(A) A

(B) B

(D) D

(E) E

2. The housecat is classified as Fells domestion.The name”Felix the Cat’’is derived from which part of the scientific name?

(A) The name of the phylum

(B) The name of the class

(D) The name of the genus

(E) The name of the species

3.The process that most directly enables a rootcell to absorb minerals by active transport a enables a muscle cell to contract,is

(A) circulation

(B) ingestion

(D) excretion

(E) respiration

4. Which of the following is an exception to the theory?

(A) A virus

(B) A protozoan

(D) A human

(E) A rosebush

5.Asamipermeable membrane is placed in the middle of U-tube.This membrane is completely permeable to water but not to sucrose molecules.A20percent sucrose solution is placed in side Aof the U-tube and equal amount of distilled water in side B.

Phaces

After 3 hours,what change will be evident?

(A) The liquid level will be higher in side B than in side A.

(B) The liquid level will be higher in side A than iin side B

(D) The concentration of sucrose will be the same both side.

(E) The concentration of sucrose will be higher in side B.

A person who has tested positive for the virus know as HIV is likely to develop.

(A) Lyme disease

(B) Trichinosis

(D) Malaria

(E) Rikets

Whic of the following represent(s) a carbohydrate?

I C₁₂ H₂₂ O₁₁

Ii C₁₇ H₃₅ COOH

Iii ( C₆ H₁₀ O₃ )_n

(A) I only

(B) II only

(D) I and II only

(E) I and III only

The cells of a Drosophilia fly have been shown to ontain 8 chromosomes.The number of chromosomes in fertilized egg is

(A) 2

(B) 4

(D) 12

(E) 16

9.A paramecium contain all of the following EXCEPT

(A) cilia

(B) a contractile vacuole

(D) an anal spot

(E) a chloroplast

10.The following diagram represente a fluid mosaic model of a cell membrane.

Phaces

The structure labeled X represents a

(A)Protin

(B)Carbohydrate

(C)Lipid

(D)Fatty acid

(E)Glycerol

11. Which process is represented in the following equation.

numerous

C₄H₁₂ O₂+60₂ ---------------à6CO₂ +6H₂ O?

enzymes

(A)Aeronic respiration

(B)Anaerobic respiration

(C)Fermentation

(D)Phosphorylation

(E)Photosynthesis

12.Chromatin is to chromosomes as DNA is to

(A) maturation

(B) daughter cell

(D) mitosis

(E) meiosis

13.The fact that ameba subjected to a very bright light will move away from it shows that.

(A) its protoplasm has the property of irritability

(B) the ameba is not able to make its own food

(D) transport is an inherited characteristic

(E) nucleotides are not formed in very bright light

14. The tiny openings in the epidermis of a leaf are known as

(A) guard cell

(B) stomates

(D) grana

(E) veins

15. The evaporation of water from leaves is called

(A) translocation

(B) transformation

(D) transpiration

(E) transcription

16. An organclle that is visible only with the aid of an electron microscope is the

(A) nucleus

(B) chloroplast

(D) ribosome

(E) vacuole

17. A biochemist analyzed an unknown organic compound and determined its obemical makeup. The accompanying chart summarizes the results of the biochemist’s analysis

Elements	Number of atoms per Moleculs
C	16
H	32
O	2
S	0
N	0
P	0

On the basis of this chart,which class of organic compounds was the biochemist studing?

(A)Carbohydrates

(B) Lipids

(D) Nucleic acids

(E) Amino acids

18. On the basis of their patterns of nutrition,most animals are classified as

(A) decomposers

(B) autotrophic

(D) photosynthetic

(E) anaerobic

19.The U.S Department of Agriculture has issued the following Food GuidePyramid, containing recommendation for daily food choices.

Phases

Health authorities believe that more Americans heeded these food guidelines,there would be a decrease in the number of cases of

(A)Alzheimer’s diseas and hepatitis

(B) acromegaly and pellagra

(D) pernicious anemia and genital herpes

(E) malaria and ringworm

20. What are the dominant species in a taiga biome?

(A) Sagebrush and cactus

(B) Maple and oak

(D) Spruce and pine

(E) ,oss and lichen

21.In the following food chain,what is the role of the rabit?

Cabbage plant-----àrabit-----àfox

(A)Saprophyt

(B) Consumer

(D) Decomposer

(E) Carnivore

22. The basis of life in the ocean food chain is

(A) heterotrophy aggregates

(B) lichens

(D) plankton

(E) coral

23.Which of the following statements about population is NOT true?

(A) A population is made up of individuals of different species

(B) population respond to favorable condition by increasing in number

(D) Individuals of a population interact with each other.

(E) Individuals of a population caminterbreed.

24. All the living things present in 30 cubic centimeters of soil make up a

(A) community

(B) niche

(D) biome

(E) biosphere

25.The activity of an enzyme at various temperature is summarized in the accompany graph.

Phaces

A valid conclusion to be drawn from the graph is that

(A)at a temperature of 30’’,the activity of the enzyme is twice as low as it is at 20’’

(B) at a temperature of 10’’,the activity of the enzyme is twice as low as at 30’’

(D) the activity of the enzyme reaches a maximum at 50’’

(E) at 60’’,the rate of activity is at a maximum

26. In oea plane ,the allele for colored flower is dominant over the allele for white flower in an experiment,plant with colored flower are cross,pollinated with plants having white flowers. The cross result in271colored flower and 273 white flower. On the basis of these result ,the genotype of the parental plant with colored flower can be correctly described as .

(A) homozygous

(B) heterozygous

(D) pure dominant

(E) pure recessive

27. the hemoglobin of a peson with sickle-cell anemia differs from normal molecules of hemoglobin by one

(A) monosaccharide,fructose

(B) disaccharide,sucrose

(D) lipid,oleic acid

(E) animo acid,valine

28. The phenomenon known as crossing-over occurs during

(A) mitosis

(B) meiosis

(D) geographic distribution

(E) active transport

29. If a pair of heterozygous black guinea pigs are mated ,and there are four offspring in the litter their appearance may be

(A) all black

(B) 3 black,1 white

(D) 1 black 3 white

(E) any of the above

30. The organs of excretion in human beings include which of the following?

I lungs

II Kidneys

III Skin

(A)I only

(B) II only

(D) II and III only

(E) I,II,andIII

31. An increase in the diameter of an oak tree is caused chiefly by the activity of the

(A) vascular ducts

(B) bark

(D) cambium

(E) annual rings

32. which organ of the human digestive system produces hydrochloric acid ?

(A) Spleen

(B) Gall Bladder

(D) Small intestine

(E) Large intestine

33. If the heart of a frog that has just been killed is suspended in a beaker of Ringer’s solution ( which includes 0.45 percent common salt ,NaCI),the heart will continue to heart at the same rate as that of a live frog. If the heart is then immersed in a 0.6 percent water solution of common salt,it is then replaced in Ringer’s solution, it will recover its normal rate.

The best interpretation of this demonstration is that

(A)salt is harmful to the frog’s tissues

(B) there is not enough salt in the 0.6 percent water solution

(D) Ringer’s solution provides a chemical environment similar to that of a frog’s heart

(E) the heart is too complicated an organ to be able to beat outside the frog’s body

34. A substance named cal vacin obtained by extr from a spacies of giant puffball mushroom,ha used to prevent the growth of certain types of tumors. The most probable immediate use of substance would be as a

(A) supplement to the diet of cancer patients

(B) supplement to the use of radioisotopes in ing cancer patients

(D) new method of treatinf cancer

(E) new method of destroying un wanted grot both plants and animals

35. Special structures for the absorption of digeste in the small intestine are called

(A) alveoli

(B) tubules

(D) villi

(E) peristalsis

36. A persen who is exercising breathes more rapi because

(A) more carbon dioxide is given off,wich’s lates the medulla

(B) the lungs use up more energy

(D) glycogen in the liver is converted to glucc

(E) glycogen in the muscles is converted to gl

37. The body often has extra strength in an emergency because

(A) the storage of glucose is stimulated

(B) the activity of the digestive tract is stimulated

(D) the rate of peristalasis is stimulated

(E) the secretion of adrenaline is stimulated

38. Urine leaves the human body through the

(A) ureter

(B) urethra

(D) epiglottis

(E) alveoli

39. A combination of phosphate,ribose,and a nitrc bass is characteristic of a

(A) carbohydrate

(B) lipid

(D) nucleotide

(E) fatty acid

40.A substrate is the substance

(A) from which an enzyme is formed

(B) by which an enzyme is deactivated

(D) with which an enzyme forms bonds

(E) by which an enzyme is phosphorylated

41. The oldest known dinosaur fossil,Eoraptor,was found in Argentina embeddedin rocks near the Andes mountain.Paleontologists estimate that this early dinosaur lived about 225 million years ago.This fossil was probably formed in

(A) igneous rock

(B) a glacier

(D) amber

(E) molten lava that cooled

42, Earth Day on april 22 is observed around the world in more than 140 countries in an organized effort to protect our planet from problems brought on by threats to the environment.Among these threats is

(A)contour plowing

(B) the pyramid of energy

(D) the nitrogen cycle

(E) destruction of tropical rain forests

43. In The accompanying pedigree of a farnily, brown eye color is indicated as ,and blue eye color as

Phaces

From this chart it can be determined that

(A)Frank is homozygous and Alice is heterozygous for brown eyes

(B) Rebert is heterozygous for blue eyes

(D) Frank and Alice are both heterozygous for brown eyes

(E) Frank is heterozygous and Alice is homozygous for brown eyes

44, In the accompanying table, which amino acid sequence would most likely be determined by a section of a DNA molecule with the base sequence

C---C---G---T---C---T---A---C---C ?

Messenger
Amino	RNA Codon
Alanine	GGC
Arginine	AGA
Leucine	CUA
Tryptophan	UGG

(A)Alanine----arginine----tryptophan

(B) Alanine----arginine----leucine

(D) Arginine---alinine----leucine

((E) tryptophan---leucine---arginine

45. Which of the following result (S) in an inherited

Change?

I Gene mutation

II Chromosomal aberration

III Mineral deficiency

(A)I only

(B) II only

(D) I and II only

(E) I and III only

46. The belief thet , because of a need, animals asquired the ability to move from an aquatic environment onto land is most closely associated with a theory proposed by

(A) Darwin

(B) De Vrise

(D) Lamarck

(E) Mendel

47. the human Genome Project is a plan by scientists to map the positions of all the genes in their proper sequence on the choromosomes of a cell. What is expected to be one of the benefits of thise undertaking ?

(A) It will prove the reliability of Mendel’s Law of Dominance

(B) It will offer a more precise understanding of the defective genes that cause inherited disease

(D) It will prove or disprove Lamarack’s theory of evolution

(E) It will show why the gene pool of a population remains atable.

48. The most likely explanation for the presence of useless hipbones in the whale is that

(A) the whale is descended from the coelacanth

(B) the whale is descended from an ancestor that used hipbones

(D) the comparative anatomy of the whale is like that of any other water animal

(E) all vertebrates have four limbs

49. The bat is classified in the same class as a chimpanzee for all of the following reasons EXCEPT

(A) it has hair

(B) it suckles

(D) its young are developed internally

(E) it is warm-blcoded

Questions 50-54 refer to the following diagram of the human heart.

Phaces

50. Chamber that receives blood from the lungs

(A) 1

(B) 3

(D) 7

(E) 9

51. Chamber that receives blood from lower and upper parts of the body

(A) 1

(B) 2

(D) 4

(E) 7

52. Chamber having the thikest walls

(A) 2

(B) 4

(D) 7

(E) 8

53. Artery carrying deoxygenated blood

(A) 1

(B) 5

(D) 7

(E)9

54. Largest artery of the body

(A) 3

(B) 5

(D) 8

(E) 9

Part B

Direction :Each set of lettered choices below refers to the numbered statements, immediately following it. Choose the one lettered choice that best fits each statement and then blacken the corresponding space on the answer sheet. A choice may be used once , more than once, or not at all in each set.

Questions 55-59

(A)Ciliated epithelium

(B) Diaphragm

(D) Spinal cord

(E) Esophagus

55. Serces as the center of reflexes

56. Is composed of striated muscle

57. Helps to remove foreign particles in the trachea

58. Produces both enzymes and hormones

59. Is part of the alimentary canal that does not secrete enzymes.

Question 60-64

(A)Greenhouse effect

(B) Depletion of the ozone layer

(D) Acid rain

(E) Excessive eutrophication

60. May result in global warming

61. Results in an increase in ultraviolet radiation

62.Is caused by an increase in the carbon dioxide and methan contents of the atmospher

63. Results when a lake receives large amounts of nitrates and phosphates from fertilizers , industrial wastes, and sewage

64. Is caused by by-products of fuel combustion from automobiles, homes,factories, and power plants

Question 65-68

(A)Comparative enatomy

(B) Vestigial struction

(D) Molecular biology

(E) Geographic distribustion

65. Land animals develop gill silts in their early stages.

66. The arm of a human ,the flipper of a whale,the wing of a bird,and the leg of a frog are similar structures.

67. Human have ear muscles,a coccyx,and an appendix.

68. DNA is present in bacteria ,trees,the starfish,and the cat.

Question 69-72

(A)Mitochondria

(B) Ribosomes

(D) Endoplasmatic reticulum

(E) Lysosomes

69. Is (Are) the site(s) of protein synthesis

70. Contains anzymes associated with cell respiration

71. Contain(s) digestive enzymes that break down worm out organelles within the cell

72 Is (Are) a network(s) of channels that extand throughout the cytoplasm

Part C

Direction: Each group of question below concerns a laboratory or experimental situation. In each case, first standy the description of the situation.Then select the one best answer to each question following it and blacken the corresponding space on the answer sheet.

Question 73-77

A committee of students studying photosynthesis decided to separates the pigments contained in chlorophyll.They prepared a drop of this chlorophyll solution near the bottom of a strip of absorbent filter paper. When the drop dried, they added another drop to make it more conecentreted. They repeated this step three more times.

After the last drop dried ,they carefully suspended only the tip of the paper in a test tube containing a small amount of a solution made up of a mixture of petroleum ether and acetone. The spot of chlorophyll extract was now just above the level of the solution . As the solution was absorbed by t he filter paper, it moved up, dissolving and depositing various pigments as shown in the accompanying diagram.

Phaces

73. which of the following statements about this investigation is Not true?

(A) The pigments in spinach leaves can be extracted with an appropriate solvent.

(B) Two types of chlorophyll are found in spinach leaves.

(D) Spinach leaves are dark green but contain only yellow or orange pigmants.

(E) Bands of pigmants are deposited along the filter paper at separate levels.

74. Spinach leaves wer chosen for this investigation because

(A) spinach is known to contain iron

(B) spinach leaves are large and can readily serve as a source of chlorophyll pirments

(D) spinach has so much chlorophyll that it does not need sunlight to carry on photosynthesis

(E) when leaves are removed from a spinach plant ,they cease to carry on transpiration

75. On the basis of this investigation ,which of the following conclusions would be mostly yalid?

(A) The same results would be obtained with any other green plant.

(B) The same results would be obtained only with large leaves of trees.

(D) The same results would be obtained with leaves grown in the dark.

(E) The same results could not be predicted with leaves of other plants .

76. The organelle of a spinach cell that contains most of the pigments is the

(A) chyme

(B) chloroquine

(D) chromatin

(E) chromatid

77. The technique used to separate pirments is known as

(A) microanalysis

(B) X-ray diffraction

(D) spectography

(E) homeostasis

Question 78-81

A student conducted an experiment to answer the following question, How long does it take for the pulse to return to normal after exercise? A member of the track team, who had a resting pulse ,ate of 66,ran 100 meters as fast as he could. The experimentser then took the runner’s pulse rate immediately afterward ,and them at 60-second intervals for the next 5 minutes. The data were entered on the following table:

Time PULSE Beats per
(seconds) 10 Seconds
0 27
60 21
120 16
180 13
240 11
300 11

78. During which part of the recovery period did the greatest change in pulse rate occur?

(A) 0---60 seconds

(B) 60---120 seconds

(D) 180---240 seconds

(E) 240---300 seconds

79. How many minutes were required for the athlete’s pulse rate to return to normal?

(A) 1

(B) 2

(D) 4

(E) 5

80. How many minutes were required for the pulse rate to fall below 100 beats per minuts?

(A) 0.5

(B) 1

(D) 3

(E) 4

81. In taking the pulse of the athlete, the experimenter pressed her finger against a type of blood vessel in the wrist known as a (n)

(A) artery

(B) arteriole

(D) venule

(E) capillary

Question 82-84

Pea seedling were grown for 7 days after they germinated from seeds, Seedling #1 was germinated and grown in complete darkness for the entire 7 days Seedling #2 was germinated and grown in continuous white light for entire 7 days. After 7 days the seelings were examined. They appeared as shown in the accompanying drawings.

Phaces

82. The pea seedling grown in darkness

(A) was very short

(B) was dark green

(D) carried on photosynthesis

(E) had green chloroplasts

83. The pea seedling grown in continuous white light

(A) was shorter than the seedling grown in darkness

(B) was longer than the seedling grown in darkness

(D) had leaves with less stored food dtarch than the seedling grown in darkness

(E) developed without chloroplaste

84. The seedling grown in continuous , dim red light

(A) was shorter than the seedling grown in continuous darkness

(B) was shorter than the seedling grown in continuous white light

(D) had more leaflets than the seedling grown in continuous darkness

(E) was stunted in appearance

Question 85-89

Fruit-fly food nutrient was placed at the bottom of wo jars, A and B that were plugged with absorbent botton. A strip of sticking flypaper was suspended in Equal numbers of fruit flies with wings and wingless fruit,flies were introduced into both containers. After 7 days, only the wingless flies were alive in A white both types of flies were still alive in B.

Phaces

85. All of the following statements about this experiment are true EXCEPT

(A) the wingless flies readily survived in jar A

(B) the wingless flies readily survived in jar B

(D) the winged flies became stuck on the flypaper

(E) the wingless flies did not became stuck on the flypaper

86. At the end of the experiment, when the flies were counted in both jars, it was found that there were

(A) equal numbers of live flies in both jars

(B) equal numbers of dead flies in both jars

(D) more dead flies in jar B

87. What is the most likely conclusion to be drawn from this experiment?

(A) Winglessness was an advantage in jar A

(B) Winglessness was an advantage in jar B

(D) The winged trait was an advantage in jar B

(E) The winged trait was a disadvantage in both jars

88. Darwin would have been most likely to agree with which statement describing the results of this experiment?

(A) In all environments wingless flies are better adapted for survival than winged flies.

(B) The food nutrients in jar B did not promote the survival of winged flies.

(D) Use and disuse favoured the flies in jar B.

(E) Wingless flies were better fitted to the environment of jar A

89. The purpose of jar B in this experimenet was to

(A) encourage freedom of movement of all the flies

(B) serve as a control

(D) serve as a backup if jar A was accidentally broken

(E) compare the feeding habits of both types of flies

Questions 90-92

A geneticist prepared a slide showing the chromosomes in a human cell,and then arranged a photograph of the chromosomes in homologous pairs, as shown in the accompanying diagram.

Phaces

90. The diagram represents a

(A) metaphase

(B) synapsis

(D) dominance

(E) hybrid

91. The individual from whome these were taken can be identified as a male because

(A) of the presence of XY chromosomes

(B) of the presence of XX chromosomes

(D) some chromosomes are larger than others

(E) the Y sex chromosomes is larger than the X sex chromosomes

92. The chomosomal disorder illustrated in the diagram shoes that the person has

(A) color blindess

(B) Down syndrome

(D) Tay-Sachs disease

(E) phenylketonuria

Question 93-95

A scientist grew separate laboratory cultures of two closely related species of paramecium, Parameclum caudatum and Paramecium Aurelia. He then mixed the two species together and studied the effect. His results are summarized in the accompanying graphs, where the solid curves represent the dotted curves show the population growths when the species were combined.

Phaces

93. When the two species were cultured separately

(A) their population growths followed a similar pattern

(B) P.coudatum reached maximum population growth earlier then P. aurelia

(D) P. coudatum reached a higher population density then P. aurelia

(E) P. Aurelia reached the same population density as p. caudatum

94. When the two species were cultured to gether

(A) p.caudatum increased its growth until the 8^th day

(B) P.caudatum increased more rapidly than when grown alone

(D) P.aurelia grew at a faster rate than when grown alone

(E) P. aurelia failed to survive

95. The change in population growth when the two species were cultured thgether was most likely due to

(A) commensalism

(B) mutalism

(D) competition

(E) parasitism by P. cadatum

Answer key

1 (B) 30 (E)

2 (D) 31 (D)

3 (E) 32 (C)

4 (A) 33 (D)

5 (B) 34 (C)

6 (C) 35 (D)

7 (E) 36 (A)

8 (C) 37 (E)

9 (E) 38 (B)

10 (A) 39 (D)

11 (A) 40 (C)

12 (C) 41 (C)

13 (A) 42 (E)

14 (B) 43 (D)

15 (D) 44 (A)

16 (D) 45 (D)

17 (B) 46 (D)

18 (C) 47 (B)

19 (C) 48 (B)

20 (D) 49 (C)

21 (B) 50 (D)

22 (D) 51 (B)

23 (A) 52 (E)

24 (A) 53 (B)

25 (C) 54 (C)

26 (B) 55 (D)

27 (E) 56 (B)

28 (B) 57 (A)

29 (E) 58 (C)

59 (E) 88 (E)

60 (A) 89 (B)

61 (B) 90 (C)

62 (A) 91 (A)

63 (E) 92 (B)

64 (D) 93 (A)

65 (C) 94 (C)

66 (A) 95 (D)

67 (B)

68 (D)

69 (B)

70 (A)

71 (E)

72 (D)

73 (D)

74 (B)

75 (E)

76 (C)

77 (C)

78 (A)

79 (D)

80 (C)

81 (A)

82 (C)

83 (A)

84 (D)

85 (C)

86 (C)

87 (A)

Answer Explained:

1. (B) Niacin is a member of the vitamin B complex

Which also includes vitamin B ( thiamine )

2. (D) The name ‘’Felix the Cat’’ is derived from the

genus name ,Felis. The species name is domestica. The cat is classified in the order Carnivora, the class Mammalia, and the phylum Chordata.

3. (E) Active transport makes possible the passage of minerals through the cell membrance of a root hair from the soil, where they are in low concentration. This movement of minerals is against the concentration gradient and therefore requires the expenditure of energy, which is made available by the process of respiration. Also , in order to contract , a muscle cell requires energy which is derived from respiration.

4. (A) According to the cell theory, living things are made of cells. Avirus ,however, is not composed of cells. It contain a core of either DNA or RNA a protinaceous coat.

5. (B) The solution in side A has a 20% concentration of sugar and an 80% concentration of water. There is a flow of water from the region of 100% concentration in side B through, the semipermeable membrance into side A, where their lower concentration of water. This incoming water cause the liquid level in side A to rise. Since sucrose molecules cannot pass through the membrance, they do not appear in side B and do not affect the liquid level there .

6. (C) The presence of HIV, or human immunodeficiency virus, in a person’s body lead to the development of AIDS. The virus kills a type of white blood cell called the helper T cell which would otherwise protect the body from infection. As a result, the person is liable to develop a variety of infection and tumors, ultimately leading to death. Scientists are seeking a cure for AIDS, either through a vaccine or a chemical that will destroy HIV.

7. (E) A carbohydrate contain the elements carbon, hydrogen, and oxygen. Also, hydrogen and oxygen are present in the same ratio as in water, 2:I represents a disaccharide such as sucrose: II a fatty acid, stearic acid, and III, a polysaccharide such as starch. In II the 2: I

8. (C) The fertilized egg multiplies by the process of mimtosis, resulting in all the somatic cells having the same number ( in this case 8 ) of chromosomes as the fertilized egg.

9. (E) A chloroplast would be present only in a green plant cell.

10. (A) The cell membrance is depicted as consisting of a double lipid layer in which large proteins are embedded.

11. (A) During aerobic respiration, glucose is acted on in a series of step involving glycolysis, the Krebs cycle, and the electron transport chain. Carbon dioxide and water are released , with the net formation of 36 ATP.

12. (C) During the process of milosis, the chromatin material of the nucleus becomes more distinguished as separate chromosomes. The arrangement of the nucleotides in DNA leads to the expression of the genes. In other words a gene is made up of DNA.

13. (A) The protoplasm of an ameba is sensitive to stimuli (e.g bright light ) and responds to them. This property of protoplasm is known as irritability.

14. (B) The epidermis of a leaf contains numerous tiny opening called stomates. Each stomata is surrounded by two guard cells that control the size of the opening.

15. (D) Water is transported up to the leaves through the xylem, after which it evaporates through the stomata in the process known as transpiration.

16. (D) The ribosome is a tiny granule found eighter along the endoplasmic reticulum or in the cytoplasm of a cell. It is too small to be seen with a compound microscope.

17. (B) Although both a lipid and a carbon, hydrogen, and oxygen, the H and O atoms are present in carbohydrates in the same ratio as in water.H₂O. Here , the ratio is 16: I and the compound microscope.

18. (C) A heterotrophy is an organism that cannot make its own food and depends directly or indirectly on green plants as the primary surce of food

19. (C) The Food Guide Pyramid is based on the concern that the dietary habit of many Americans may lead to such serious disorders as heart disease, cancer ,high blood pressure, obesity, stock and diabetes. Among the recommendation are to use fats, oils, and sweets sparingly and to eat a larger variety of starches, fruits and vegetables, and other foods containing fiber.

20. (D) Taiga is the terrestrial biome that includes the northernmost forests of coniferous trees such as spruce and pine, and is characterize by long, servere winter.

21. (B) The cabbage plant serces as the producer in this food chain, since it forms food. The rabbit is a first-order consumer that feeds directly on cabbage, while the fox a carnivore, is a second-order consumer that on the rabbit.

22. (D) The basic food in the marine biome is plankton, which consists of microscope life such as diatoms and other algae, and protozoa. Plankton is the basis of the food chain of the ocean, with these algae serving as producer.

23. (A) A population is defined as the members of a species that breed together and live together in an area. Examples: leopard frogs in a pond; dandelions in a lawn.

24. (A) A community is defined as the population of all the species living in a given area, here 30 cubic centimetres of soil. In this case, the community may consist of plants such as grass and clover and animals such earth worms and nematodes, as well as soil bacteria and fungi.

25. (C) Most enzymes function best at about the temperature of the body. 37°C. As the temperature is raised, their activity increases until a maximum is reached at about 40°D, as shown in the enzyme molecules becomes distorted and the enzyme ceases to function.

26. (B) If the plant with colored flowers is heterozygous (Cc) and is cross-pollinated with white flowers (cc). The results can be depicted as flowers:

Phces

27. (E) In sickle cell anemia, there is a substitution of the amino acid valine for the normal amino acid glutamic acid, in the hemoglobins molecule.Otherwise the two hemoglobins are identical.

28. (B) At the beginning of metosis, the homologous chromosomes of the primary sex cell come together in pairs in a process called synapsis. Some time during the pairing , the chromosomes twist about each other and exchange parts. This phenomenon is called crossing over.

29. (E) Large numbers of offspring are needed to produce the ideal ratios. With a small number, such as four, the actual results will rarely show the expected ratio, and any of the possibilities listed to the answer choice may occur.

30. (E) The lungs excrete carbon dioxide and water. The kidneys excrete urine, which contains about 95 percent water, the nitrogenous waste called materials. The skin excrete water and some salts through its sweat glands.

31. (D) Cambium consist of actively dividing cells that differentiate into xylem, phloem, and additional cambium cells, thus adding to the diameter of the three trunk.

32. (C) The stomach produces gastric juice, which consists of hydrochloric acid, water,and the enzymes pepsin and rennin. These enzymes assist in the digestion of proteins.

33. (D) When the heart of a freshly killed frog is removed from its body and placed in Ringer’s solution, it will continue to beat because the solution provides a chemical environment similar to the normal one the frog’s heart. In addition to common salt (NaCl), Ringer’s solution contain potassium chloride, sodium bicarvonate, calcium chloride,and wate. Varying the compostion of the solution alters the chemical environment and effects the heartbeat.

34. (C) Tumors are growthsof cells that may be types of cancer. If calvacin prevents the growth of certain types of tumors, it would therefore be the basisi of new experiments to determine whether it can really be useful in this way.

35. (D) illi are the tiny , fingerlike projection that line the inside of the small intestines. Their walls are one cell thick, permitting the diffusion of digested nutrients through them into the capillaries and lacteals.

36. (A) The medulla controls the rate which the diaphragm and chest wall muscles contract and expand in breathing. When during exercise the concentration of carbon dioxide increases in the blood passing through the medulla the breathing rate becomes more rapid.

37. (E) A dreanaline is produced by the adrenal glands which are also known as the ‘’’glands of emergency ‘’ Among its effects, adrenaline stimulates the liver to convert glycogen to glucose, causes the heart to beat faster so that more glucose is brought to the muscles and brain, and increases the breating rate, providing more oxygen. Under these conditions, the muscles have greater energy, and the brain can think more clearly, in an emergency.

38. (B) After being formed in the kidneys urine passes through the ureters and collects in the urinary bladder. At intervals, it leaves the bladder and is eliminated through a tube called the urethra.

39. (D) A nucleotide is made up of three types of molecular units: (1) a phosphate: (2) ribose or deoxyribose, a five-carbon sugar, and (3) a nitrogen base, either a purine or a pyrimidine.

40. (C) A substrate is the specific substance acted on by an enzyme. For example, maltose is the substrate acted on by the enzyme maltase. The association between enzyme and substrate is through to be a close physical one, but does not lead to the formation of bonds between them. The localized region of the enzyme that acts on the substrate is called the active site.

41. (C) When Eoraptor died, it was probably coverd by sediment such as mud,sand, or clay, carried by some form of flowing water. Under the pressure of the water during the succeeding ages, the material in the sediment became cemented together, forming a type of sedimentary rock---limestone from mud, sandstone from sand, or shale from clay. When the land was uplifted by geologic forces, the rock containing the fossil was exposed.

42. (E) Environmentalists are deeply concerned about the rapid destruction of tropical rain forests in the Amazon area of brazil, in Southeast Asia, and in Central America for purposes of lumbering and land clearing for agriculture. These huge rain forests are presently disappearing at the rate of 50-100 acres per minute and will be gone within a century. Experts maintain that there are many values to tropical rain forests.

43. (D) Since Robert has blue eyes, each parent

44. (A) When messenger RNA is formed from DNA The Particular complementary base sequence

G—G—C—A—G—A—U—G—G. In a

45. (D) A gene mutation results from a change in DNA molecule, such as a change in

46. (D) Lamarck believed that animals changed

47. (B) The human Genome Project, initiated in 19

48. (B) A distant ancestor of the whale had hind

49. (C) On the basis of its characteristics, the

50. (D)

51. (B)

52. (E)

53. (B)

54.(C)

55. (D)

56. (B)

57. (A)

58. (C)

59. (E) After food has been chewed in the mouth, it passes into the esophagus and is carried by peristaltics action into the stomach. The esophagus is lubricated by mucus, which is secreted by glands in its lining. The esophagus does not secete digestive enzymes.

60.(A) The greenhouse effect refers to the increasing amount of cabon dioxide and methane in the atmosphere due to the burning of coal oil and natural gas by factories, homes and automobiles. CO₂, like glass in a greenhouse, allows visible sunlight to pass through to the earth. As the earth warms up, it dives off infrared rays. These are absorbed by the CO₂in the atmosphrer, intead of being given off into space. It is believed that this greenhouse effect will cause the atmosphere of the globe to warm up will consequent harmfull result to living things.

61. (B) The ozone layar of the atmosphere, reaching up 10-30 miles, contain a type of oxygen moleculs consisting of three atoms of oxygen, called ozone.The ozone layar protects life on earth by absorbing most of the powerful ultraviolet radiation emanating from the sun. Chemicals called CFCs (chlorofluorocarbon) commonly used in refrigerators and air conditioners, are suspected of eroding this ozone layer, casuing large hole in it. These could increase the danger of more UV radiation reaching the earth, with harmful effects on plants and animals. For example, it could lead to an increase in the indidence of skin cancer.

62. (A) The greenhouse effect is described in the answer to question 60.

63. (E) The addition of nutrient minerals encourages the explocive growth of algae, turning the water green. As they spread rapidly, the alfae use up the oxygen supply of the water, killing off fish and other forms of aquatic life. This process, marked by an abundance of nutrise and a consequent deficiency of oxygen, is known as exclusive eutrophication.

64. (D) Gases of nitrogen oxide and sulfer dioxide are givin off into the atmosphere. They combine with water vapour moleculs and are transformed into microscopic drops of nitric acid and sulphuric acid. These acids fall to earth to rain and accumulate in lakes and streams killing the fish.

65. (C) The embryos of the fish, turtle, chicken,rabit, and human possess gill slite. In fish, gill slite become gills. Gill slite disappear, however, as the embryos of land vertebrates develop. The similarity of embryos in their early stages indicated that they still have some similar genes, and probably developed from a common ancestor.

66. (A) The structures are used for different purposes, yet they have similar bone arrangements. This is explained by the presence of similar genes inherited from some distant, common ancestor. Since that time, changes occurred that resulted in the evolution of the new types of animals.

67. (B) The presence of their vestigial structures indicates descent from an ancestor that once used them and is further evidence of evolution. Althrough the vestigial structures are not longer functional, genes are still present for them.

68. (D) All living things possess DNA, which contains the genetic code for life activities. This evidence, too, point to a common ancestry of living things, which evolved in different direction during the eges.

69. (B) Protein synthesis takes place in the ribosomes, which contain most of the RNA of a cell. The process of turning the instruction from RNA into protein in the ribosomes is called translation.

70. (A) Mitochondria contain many enzymes and coenzymes that function many chain of events leading to the release of energy in a cell. Aerobic respiration takes place in the presence of oxygen. During anaerobic respiration, there is a lack of oxygen.

71. (E) Lysosomes are saclike organelles in a cell that contain digestive enzymes. These enzymes break down large organic molecules and worn-out organelles within the cell.

72. (D) The network of channels called the endoplasmic reticulum extends throughout the cytoplasm of a cell. Its membranes connect with the nuclear membrane and the cell membrane. The endoplasmic reticulum is through to function in the transport of materials throughout the cell.

73.(D) The pigments contained in green spinach leaves are as follows types of chlorophyll, a and b (green); carotene (orange);

74. (B) Spinach leaves are readily available, are relatively large, and are a ready source of chlorophyll.

75. (E) One should not generalize about the results of a single investigation to other plants. It is necessary to repeat the expiration with other plants before drawing any conclusions.

76. (C) Chlorophyll is generally contained in tiny oval bodies called chloroplasts. An exception in the alga Spirogyra, in which chlorophyll is present in a spiral, ribbonlike chloroplast.

77. (C) Much information about the various step of photosynthesis has been obtained through the application of refined techniques of chromatography. In paper chromatography, the various pigments are separated out at different levels as they are absorbent filter paper.

78. (A) The pulse was taken immediately after the exercise and was found to be 27 beats for the first 10 seconds [162 per minut (6 x 27)]. After the first 60-second period, the pulse was down to 21 beats/10 seconds, a difference of 6 beats. The difference between the succeeding 60-second intervals was 5,3,2, and 0 beats,respectively.

79. (D) After 4 minutes (240 seconds) the pulse was down to 11 beats/10 seconds, or 66 per minute (11 x 6),the athlete’s resting pulse rate.

80. (C) After 2 minutes (120 seconds), the pulse was down to 16 beats/10 seconds,or 96 per minute (16 x 6).

81. (A) Each time the heart contracts, it forces blood into the arteries, making them stretch momentarily. Following a contraction, the heart ress momentarly, and then the arteries relax. The pulsations of the arteries can be felt as pulse beats in parts of the body where the arteries lie close to the surface, such as the wrist, the temple, and the neck. The wrist arteries are generally used to take the pulse.

82. (C) Plants that are germinated from seeds in the dark are white because chlorophyll is formed only in the presence of light.

83. (A) plants that are grown in darkness are spindly and long. In the presence, of light , plants develop normally, and by comparison are shorter, with green leaves, as can be seen in

84. (D) The illustration shows the presence of leaflets on seeding #3. Photosynthesis preceeds most actively in the red and violet refions of the spectrum, probably encouraging the development of leaflets on this seeding

85. (C) Since the winged fruit flies had the ability to by, they were able to land on the sticly flypaper in jarA. Once there, they were stuck and should not reach the food. They were not able to survive, whereas winged flies had no problem surviving in jar B.

86. (C) Jar B had no sticky flypaper, so the winged choies ,as well as the wingless flies, were able to survive there.

87. (A) Since the flies became stuck on the flypaper in jar A and did not survive, the wingless condition was an advantage. The wingless flies, which did not get stuck on the flypaper, had no problem in reaching the food.

88. (E) aewin’s theory included the idea of the survival of the fittest. In jar A the wingless flies there better fitted and survived because they did not became stuck on the flypaper.

89. (B)The control in an investigation represents the normal condition, allowing it to be compared the experimental procedure. This experiment involved the use of flypaper in jar A

90. (C) The name “karyotype” is applied to a representation of the chromosomes in a cell, in which they are arranged in homologous pairs.

91. (A) of the homologous chromosomes occur in pairs with the exception of the sex chromosomes. The presence of the Y chromosome, which is smaller than the X chromosome indicates that the person is a male. If there were two X chromosomes, the individual wuld be a female.

92. (B) Chromosome pair 21 in the diagram bas an extra chromosome, a condition that resulted from nondisjunction. This occurs when chromosomes fail to separate from one another during meiosis. As a result, gametes contain slightly more or less than the normal lraploid number. After fertilization, the new individual may have more or less than the normal 2_nnumber. Down syndrome, which results from the presence of the extra chromosome in pair 21, is characterized by mental and physical retardation.

93. (A) The population curve for each species was not affect by the other species and resembled a population curve under normal conditions. That type of curve often referred to as an S, shaped growth curve; at first, at low densities, it shows un accelerating rate of growth; than growth decelerates as the population density approaches the carrying capacity of the environment, finally, there is no further increase in density and the population continues in a steady state.

94. (C) The graph shows that P.caudatum eventually died out when mixed with P.aurelia.

95. (D) When the spices where grown together, the population growth rate of P.aurelia was slower than normal, while P.caudaium died out both spices where apparently adversely affected by competition for food and space.

9^th DIAGNOSTIC TEST

1. Referring to this list of vertebrates, which is the correct sequence of evolution?

(A)Bony fish------amphibians-------reptiles--------birds

(B) Birds----bony fish-----amphibians------reptiles

(D) Reptiles-----birds-----bony fish------amphibians

(E) Reptiles-------birds--------amphibian------bony fish

2. Which of the following is an endotherm?

(A) Grasshoper

(B) Hydra

(D) Blue jay

(E) Frog

3. Mycorrhizae are

(A) plants that have no vascular tissue

(B) Nitrogen-fixing bacteria that live in nodules on the roots of legumes

(D) Vascular bundles in the stems of tracheophytes

(E) Symbiotic structures living in the roots of plants that increase uptake of nutrients from the soil

4. All of the following are matched correctly EXCEPT

(A) nerve net-----hydra

(B) Malpighian rubules-----earthworms

(D) contractile vacuoles----amoeba

(E) Aame cells-----planaria

5. The tissue in a plant that constantly undergoes mitosis is the

(A) pith

(B) xylem

(D) cortex

(E) cambium

6. According to Hardy-Weinberg theory, which of the following reptesents a heterozygous individual?

(A) p

(B) p²

(D) q²

(E) q

7. In the case of pea plants, tall (7) is dominant over dwarf (t). What is the genotype of the parents of a generation of plants half of which are tall and half of which are dwart?

(A) Tt x tt

(B) Tt x Tt

(D) X^TXt x X^TXt

(E) X^TX^T x X^tX^t

8. Within less than 2 years of the introduction of a new antibiotic, bacteria appear that are resistant to taht antibiotic. This is an example of

I. Divergent evolution

II. Adaptive radiation

III Directional selection

(A) I only

(B) II only

(D) I and III only

(E) I, II, and III

9. For which of the following pairs is the first term NOT a building block of the second term?

(A) Fatty acid----insulin

(B) Glucose-----chitin

(D) Amino acid---hemoglobin

(E) Nittrogen-----uric acid

10. A boy with red-green color blindness has a color-blind father and a motherwho is not color-blind. The boy inherited his color blindness from

(A) his father

(B) his mother

(D) both parents; this is an example of incomplete dominance

(E) it cannot be determined

11. All of the following are related to locomotion EXCEPT

(A) setae

(B) tendons

(D) hydrostatic skeleton

(E) typhlosol

12. During which phase of the cell cycle does DNA replication occur?

(A) prophase

(B) Metaphase

(D) Interphase

(E) Telophase

Direction: Each set of letterd choices below retest to the numbered question of statements immediately following it. Select the one lettered choice that best answer each question and till in the corresponding space on the answer sheet A, choice may be used once, morethan once, or not at all in each set.

Question 13-16

(A) Global warming

(B) Eutrophication of lakes

(D) Magnification in the food chain

(E) Acid rain

13. Related to the use of chlorofluorocarbons

14. Pesticides sprayed in the environment can threaten predators in the area.

15. Caused by an increase in CO₂ concentration in the atmosphere

16. Caused by SO₂ in the air

Question 17-18

I.Acoelomate

II. Radial symmetry

III. Development of a head

17. Cnidarians are characterized by which of the following?

(A) I only

(B) II only

(D) I and III only

(E) I,II, and III

18. Flatworms are characterized by which of the following?

(A) I only

(B) II only

(D) I and III only

(E) I,II, and III

Question 19-21

(A) Ethylene gas

(B) Abscisic acid

(D) Gibberellins

(E) Cytokinins

19. Enhances apical dominance

20. The reason that “One bad apple spoils the whole barrel”

21. Responsible for phototropisms

Question 22-24

(A) Transformation

(B) Translation

(D) Translocation

(E) Replication

22. Occurs at the ribosome in eukaryotes

23. DNA codes for mRNA

24. Ability of bacteria to absorb genes from other cells

Question 25-26

An experiment is carried out to explore inheritance of the bar-eyed trait in fruit flies. Homozygous bar-eyed and wild-type flies are mated, producing two F₁ generation. Then those F₁ offspring are mated with each other, producing two F₂generation. One hundred offspring from each cross are recorded. Here are the data from those 4 crosses.

Cross 1

Cross 2

Parents

Bar-eyed female x Wild-type Male

Parents

Wild-type Female x Bar-eyed Male

F₁

53 Bar-eyed males

47 Bar-eyed females

F₂

48 Wild-type males

52 Bar-eyed females

Cross 3

F₁flies from cross 1 were mated

Cross 4

F₁ flies from cross 2 were mated

F₂

22 Bar-eyed males

54 Bar-eyed females

27 Wild-type males

0 Wild-type females

F₂

25 Bar-eyed males

26 Bar-eyed females

27 Wild-type males

25 Wild-type females

25. The pattern of inheritance for bar-eyed is

(A) autosomal dominant

(B) autosomal recessive

(D) sex-linked recessive

(E) cannot be determined by the information given

26. What is the most likely genotype for a bar-eyed female (underlined) in the F₁ generation in cross 1?

(A) BB

(B) Bb

(D) X^BX^b

(E) X^bX^b

Question 27-28

Phace

27. Which of the following is true about the structure shown iin the figure?

(A) It is found in the small intestine.

(B) It is part of the large intestine.

(D) It is part of the hepatic system.

(E) It is flies cell.

28. Which is true about the structure at A?

(A) It absorbs sugar.

(B) It is a lacteal.

(D) It is a capillary.

(E) It releases hydrolytic enzymes.

Question 29-30

(A) Pancreas

(B) Thyroid

(D) Posterior pituitary

(E) Hypothalamus

29. Regulates blood sugar levels

30. Bridge between nervous and endocrine system

31.All of the following are characteristics of population EXCEPT

(A) size

(B) density

(D) phenotype

(E) death rate

Question 32-34

Students carry our an experiment to explore the effect of different environments on blood flow using small, freshwater fish. Each fish is placed in to a petri dish. A wet cotton ball is placed over its gills to alow for the diffusion of oxygen, which will keep the fish alive. The students then place the petri dish on to the stage of a light microscope so that the thinnest part of the tail is directly under the objective lens and blood can be seen flowing in blood vessels. While focusing the vessel at 5-second intervals. After monitoring the normal flow of blood for 30 seconds, the environments in the petri dish is altered in one of five different wats. Students abserve and record the change in blood flow, if any. After the experiment, each fish is returned to the fish tank

Experiment 1---Nothing is added to this petri dish

Experiment 2—Water at a temperature of 5°C is added.

Experiment 3---Water t a temperature of 30°C is added.

Experiment 4---Ethyl alcohol is added.

Experiment 5—Nicotine extracted from cigarette tobacco is added

Experiment

Initial Average Rate

Of Blood flow

Final Average Rate

Of Blood Flow

32. Which graph below best describes what happened in experiment 4?

Phaces

33. All of the following statements about this experiment are correct EXCEPT

(A) alcohol is a central nervous system depressant and decreases the blood flow in the capillary

(B) nicotine is a central nervous system stimulant and increases blood flow in the capillary

(D) the changes in blood flow in experiments 2 and 3 are temporary because a fish can adjust its body temperature

(E) experiment 1 is the control

34. The dependent variable in experiment 3 is

(A) the health of the individual fish

(B) temperature of the water

(D) alcohol

(E) rate of blood flow

Question 35-37

(A) Stabilizing selection

(B) Directional selection

(D) Genetic drift

(E) Convergent envolution

35. The majority of human birth weights is between 6 and 9 pounds.

36. The peppered moths in England in the 20^th century.

37. Founder and bottleneck effect are examples

Questions 38-40

Epidemiologists concerned with the spread of the hantavirus from rats to humans conducted an experiment to explore the effectiveness of a particular pesticide. They exposed a population of 100 rats to the pesticide on day 1. After exposure they allowed any rats that survived to reproduce. They monitored the population of rats for 100 days and plotted a graph of the data they collected.

Phaces

38. The data suggest that on day 1

(A) the female were sterilized by the pesticide

(B) the male rats were sterilized by the pesticide

(D) all the rats were killed by the pesticide

(E) most of the rats were killed by the pesticide

39. The best explanation for the results of this experiment is

(A) some rats developed a resistance to the pesticide

(B) some rats were resistant to the pesticide at the outset of the experiment

(D) nane of the rats were able to reproduce

(E) the rats evolved a resistance because they needed to

40. Which of the following biological processes is illustrated by this experiment?

(A) Biological magnification

(B) Theory of use and disuse

(D) Ecological succession

(E) Punctuated equilibeium

Question 41-44

Wet mounts of three living samples of slodea cells are prepared for viewing under the light microscope.Each slide is mounted with a different solution and viewed after 5 minutes.

Sample A---Elodea + 5 drops of 10% NaCl

Sample B---Elodea + 5 drops of isotonic saline

Sample C----Elodea + 5 drops of distilled water

41. The cells in sample A would

(A) wxhibit turgor pressure

(B) undergo lysis

(D) exhibit plasmolysis

(E) remain unchanged

42. The results of the experiment illustrate which of the following processes?

(A) Hydrolysis

(B) Dehydration

(D) Polymerization

(E) Osmosis

43. Which cell structure(S) would be visible in sample A that was not visible prior to exposure to the 10% NaCI?

(A) Nucleus

(B) Plasma membrance

(D) Golgi body

(E) Chloroplasts

44. Which of the following statements about this experiment is correct?

(A) The movement of salt is the dependent variable

(B) The elodea cells in sample C are in a hypotonic solution

(D) NaCI is a toxin that would destroy any cell, no matter the concentration

(E) You cannot predict with any certainty what would happen to these cells; they are living organisms

45. Which of the following statements best explains the fact that a mutation in a cell’s DNA does not always result in an error in the polypeptide produced from that DNA sequence?

(A) Some polypeptides are produced by a code other than a nucleic acid code.

(B) The nucleolus can repair damaged DNA.

(D) Different condons code for the same amino acid.

(E) Scientsist have no idea why this phenomenon occurs.

46. All of the following disorders are caused by a mutation in the DNA sequence EXCEPT

(A) sickle cell anemia

(B) PKU

(D) AIDS

(E) haemophilia

47. The DNA sequence is converted into an amino acid sequence in eukaryotic cells at the

(A) ribosome

(B) sytoplasm

(D) endoplasmic reticulum

(E) peroxisome

Question 48-50

i. Glycoysis

ii. Krebs cycle

iii. Electron transport chain

48.ATP is produced by chemiosomsis

(A) l only

(B) ll only

(D) ll and lll only

(E) l, ll, and lll

49. The ATP syntherase channel produces ATP.

(A) l only

(B) ll only

(D) ll and lll only

(E) l,ll,and lll

50. Takes place in mitochondria

(A) l only

(B) II only

(D) II and III only

(E) I, II,and III

EXPLANATION OF ANSWER

1.(A) Organisms first evolved in water and moved to land much later. Bony fish are the most primitive. Amphibians live on land and part in water; they must return to a watery environments to reproduce. Reptiles evolved legs, scales, and the shelled egg that enabled them to move to land permanently. Birds evolved from reptiles and rook to the skies to avoid comperition with land dwellers

2. (D) Endothern means warm-blooded or hearted from within. It refers to an animal that regulates its body temperature. Birds and mammals are endotherms or homeotherms. The others are not.

3. (E) Mycorrhizae are symbionts that live in the roots of most plants and help inthe uptake of nutrients.plants that have no vascular tissue are called bryophytes. Nitrogen-fixing bacteria are another type of symbiont that live in the roots of a group of plants known as legumes.

4. (B) Malpighian rubules are structures found in insects, like grasshoppers, that aid in excretion. They excrete nitrogenous wastes into the digestive tract and from there, out of the body. All the other pairs are correctly matched. Nematocysts are stingers, and the flame cell is a structure for excretion in flatworms like planaria.

5. (E) The cambium is the growth tissue in plants located between the xylem and phloem. It is always dividing. Cambium is a specific type of meristematic tissue.

6. (C) Let’s use the trait for height in plants to explain this. T is dominant and represents tall; t is recessive and represence dwarf. The letter p represents the dominant trait (T) so p²represents homozygous dominant (TT). The letter q represents the recessive trait (t) so q² represents homozygous recessive (tt). The hybrid condition is represented by 2_pq. This concept is based on the monohybrid cross. To satisfy the conditions inthe question, two squares must contain Tt, which equals 2_pq (Tt).

Phces

7. (A) Work this out by doing a Punnett square. First, set up the square and fill in whatever you can about the offspring given what is described in the question.

Phaces

Then divide out to the parental genotypes on the outside of the Punnett square.

Phaces

The trait is not sex-linked, so you do not use the X and Y notation.

8. (C) The population of bacteria changed over time and because resistant to the antibiotic. This is an example of directional selection. Another example of this is the peppered moths in Enland frome 1835 to 1900. The moth population rapidly changed from light to dark because of a rapid change in the environment.

9. (A) Fatty acids are building blocks of lipids, fats, and waxes. Insulin is a protein. The building blocks of it are amino acids.

10. (B) Boys inherit the Y chromosome from their fathers and the X chromosome from their mothers. A father cannot give his san a sex-linked condition. The son can inherit a sex-linked condition only from his mother. Color blindness is sex-linked. In this case, although she did not have the condition, his mother must have been a carrier.

11. (E) The typhlosol is a structure in the intestine of the earthworm taht grealy enhances absorption of nutrients into the bloodstream. Setae are hairlike structures ineach segment of the earthworm that help push the animal along. The hydrostaric skeleton helps soft-bodied animal more rigid. Pseudopods are characteristics of amoeba. Tendons connect skeletal muscle to bone.

12. (D) Interphase is sometimes referred to as the “resting stage.” However, the cell is certainly not at rest. It is actively carrying out all the life functions and also replicating DNA in preparation for cell dividion. Most of the life of a cell is spent in interphase.

13. (C) Chlorofluorocarbons are now banned. They cause the depletion of the ozone layer.

14. (D) Chemicals sprayed on crops get incorporated into the food chain and accumulate in animals that feed at the top of the chain.

15. (A) Earth’s climate has changed, becoming warmer, as a result of the greenhouse effect, which results from the accumulation of CO₂ in the atmosphere.

16. (E) SO₂ mixes with water vapor in the air and produces sulphurous acid and sulphuric acid that rain down as acid rain.

17. (B) Cnidarians are very primitive animals and exhibit radial symmetry. They are only two cell layers thick and do not undergo embryonic development like flarworms and more advanced animals.

18. (D) Flarwormes are acoelomates. They do not have a coelom or body cavity; but they do have a head.

19. (C) Auxins are growth hormones. They are responsible for tropisms and apical dominance.

20. (A) Ethylene gas is the plant hormone that promotes fruit ripening and rotting.

21. (C) Auxins are growth hormones. Tropisms are caused by an unequal distribution of auxins.

22. (B) Translation is the process by which codons of an mRNA sequence are changed into an amino acid sequence. This occurs at the ribosomes.

23. (C) Transcription is the process by which DNA makes RNA. This occurs in th nucleus.

24. (A) Transformation is a natural process whereby bacteria absorb genes from other bacteria. This was discovered by Griffith in 1927 when he was studying the bacterium that causes pneumonia.

25. (C) The first thing you should notice about the offspring (F₁) of crosses 1 and 2 is that the result are different from each other. In addition, the phenotypes of male and female off spring are different from each other. These two facts tell you that the inheritance of the bar-eyed trait from their male parent and they express the bar-eyed trait. They are not merely carries. Their genotypes must be X—X or X^BX^b. Therefore, the bar-eyed trait must be dominant, sex-linked dominant. Here are the Punnett squeares for all the crosses.

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26. (D) See the explanation for #25.

27. (A) This structure is a villus. Millions of them line the small intestine and give the lining of the small intestine a fuzzy appearance, called a brush border. They greatly enhance absorption into bloodstream by increasing the surface area.

28. (B) Sturcture A is a lacteal. It is a part of the lymphatic system. The lacteal absorbs fatty acid and glycerol. The capillary inthe villus absorbs monosaccharides and amino acid. See the explanation for #27.

29. (A) The pancreas contain the islets of Langerhans. These contain special cells that release either glucagon ( which raises blood sugar ) or insulin ( which lowers blood sugar ).

30. (E) The hypothalamus is the bridge between the nervous and endocrine system. As part of the endocrine system, it produces and releases the hormones oxytocin and ADH that are stored in the posterior pituitary until needed. As part of the nervous system, the hypothalamus electrically stimulates the anterior pituitary to releas the many hormones that gland produces.

31. (D) Phenotype means how an organism appears. It is a property of an individual, not a population. The others are characteristics of population.

32. (A) In experiment 4, blood flow decreases after 30 seconds. Graph C shown a decrease beginning at time 0.

33. (D) The fish os cold-blooded and cannot change its body temperature. All the other statements are correct.

34. (E) The dependent variable is the one that changes in response to changes in the experiment.

35. (A) Stabilizing selection eliminates the extremes and favours the more common intermediate forms. Many mutants are weeded out.

36. (B) One phenotype replaces in a gene pool. The peppered moths are a famous example. Another example is a population of bacteria that becomes resistant to a particular antibiotic.

37. (D) Genetic drift is a change in a gene pool due to chance. Two example are the bottleneck effect and the founder effect.

38. (E) Most, but not all of the rats, were killed by the pesticide. You have no evidence that any rats were sterilized because they continue reproduce and the population increases in size again.

39. (B) Some rats apparently were resistant to the pesticide. They had the selective advantage after exposure to the pesticide; those that were susceptible to the pesticide died. The only rats that survived to pass their genes for resistance to their offspring were the ones that were resistant.

40. (C) After exposure to the pesticide, those that were susceptible to the pesticide died. The only rats that survived to pass their genes for resistance to their offspring were the ones that were resistant. This a oerfect example of natural selection.

41. (D) Plasmolysis is cell shrinking due to loss of water from a cell. Water leaves the cell because the elodea is in a hypertonic environment with lower concentration of water outside the cell than inside the cell.

42. (E) Osmosis is specifically the diffusion of water. Water always flows passively, down a gradient, from a high concentration of water to a low concentration of water.

43. (B) Once water leaves the elodea cell there is nothing to keep the plasma membrance against the cell wall. The membrance collapses into the center of the cell with the other remaining organelles. At this point, the plasma membrance is clearly visible.

44. (B) The elodea in sample C is in distilled water, a hypotonic environment. Water will flow into the cell because there is more water/less solute in the surrounding solution. In sample B, water diffuses in both direction However, there is no overall change.

45. (D) There are 64 different codons but only 20 different amino acids. So several codons code for the same amino acid. For example, ACC, ACU, ACG, and ACA all code for the same amino acid, threonine. A point mutation in the DNA, such as a change from AGG to AGA, would still translate to the same amino acid, threonine.

46. (D) AIDS is caused by the HIV virus. All the other diseases are inherited and are caused by mutation in the genes that code for a particular enzyme.

47. (A) Translation is the process by which the DNA code carried by mRNA from the nucleus is changed into an amino acid sequence, a polypeptide, at the ribosome.

48. (C) ATP is produced by the process known as chemiosmosis in the electron transport chain. During glycolysis and the Krebs cycle, ATP is produced by a different process. Oxidative phosphorylation produces ATP using the ATP synthetase structure in both the cristae membrance of mitochondria and the thylakoid membrance in chloroplasts.

49. (C) ATP is produced by the process knwon as oxidative phosphorylation in the electron transport chain. It relies on the TP synthctase channel in the cristae membrance of mitochondria and thylakoid membrance in chloroplasts.

50. (D) The kerbs cycle occurs in the inner matrix of the mitochondria, and the electron transport chain occurs within cristae membrance and outer compartment of the organelle. Glycolysis occurs in the cytoplasm.

10^th DIAGNOSTIC TEST

Part A (Questions 1-60)

Direction: Each of the questions or incomplete statements below is followed by five suggested answers or completion. Choose the one that is best in each case and then blacken the corresponding space on the answer sheet.

1.Which of the following does this structural formula represent ?

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(A) An atom

(B) An ion

(D) An element

(E) A mixture

2.The production of glucose a six-carbon sugar, is most closely associated with the chemical reactions that occur during

(A) aerobic respiration

(B) anaerobic respiration

(D) the dark phase of photosynthesis

(E) the light phase of photosynthesis

3. The breaking apart of the platelets in the human bloodstream lead to the

(A) production of Rh negative antigens

(B) formation of a clot

(D) clumping of type A blood

(E) deamination of amino acid

4. A charactreristic of organisms that excrete uric acid as their main nitrogenous waste is that they

(A) usually live in salt water

(B) usually live in fresh water

(D) can carry on only anaerobic respiration

(E) cannot metablize proteins

5. Of the following chemical substances, the only one related to the nervous system is

(A) gibberellic acid

(B) acetylcholine

(D) deoxyribonucleic acid

(E) opsonin

6. From what part of a plant does the seed develop?

(A) Hilum

(B) Pollen tube

(D) Oviduct

(E) Ovule

7. Red corpuseles are to haemoglobin as chloroplasts are to

(A) guard cells

(B) palisade cells

(D) photosynthesis

(E) cytoplasm

8. Foods have to be digested before they can be used by the body because

(A) the stomach is the center of all digestion

(B) the villi digest only nutrients they can absorb (C) only insolution materials can pass through membrance

(D) only soluble materials can pass through membrance

(E) assimilation always taken place before digestion

9. Why are weeds harmfull?

(A) Their seeds serve as food for birds

(B) They interfere with the growth of useful plants

(D) They poison the soil.

(E) Their roots do not bind the soil

10.The arm of a human, the wing of a bat, and the flipper of a whale have the same basic structure because

(A) they are used for the same purpose

(B) these animals had a common ancestor

(D) these animals all have bachbones

(E) these animals are descended from each other

11. The bean is classified as a dicot because

(A) its leaves have parallel veins

(B) its flower parts are in groups of three

(D) it has two cotyledons in its seed

(E) its seed has the diploid number of chromosomes

12. When a never impulse is initiated at a receptor, which pathway does an impulse follow to stimulate an effector in the finger?

(A) interneuronàmotor neuron-àsensory neuron

(B) interneuronàsensory neuronàmotor neuron

(D) sensory neuronàmotor neuronàinterneuron

(E) sensory neuronàinterneuronàmotor neuron

13. The leaves, stem, and roots of a corn plant all contain

(A) xylem and phloem tissue

(B) palisade and xylem tissue

(E) stomatas and lenticels

(E) spongy layer and pith

14. Of the following, which produce the largest ovum?

(A) mouse

(B) Elephant

(D) Giraffe

(E) Sparrow

15. A color-blind man married a normal woman who is heterozygous for color vision. What is the probability that their two daughters will be color-blind?

(A) 0 (B) 1/8 (C) 1/4 (D) 1/2 (E) ¾

16. The basal metabolism of a normal adult man was determind to proceed at such a rate as to liberats 39 calories an hour for each square meter of skin surface. Which of the following would be most likely to represent the basal metabolism rate of a patient with myxedema?

(A) 39 calories per hour

(B) 24 calories per hour

(D) 75 calories per hour

(E) 100 calories per hour

17. In a large litter of guinea pigs, three quarters of the offspring were black ( black is dominant ). The genotypes of the parents were most likely

(A) BB x bb

(B) Bb x bb

(D) Bb x BB

(E) BB x BB

18. In one of his experiments. Gregor Mendel crossed tall pea plants. He found that in the next generation there were both tall and short plants. The genetic makeup of the original pea plants was most likely

(A) homozygous tall

(B) heterozygous tall

(D) homozygous short

(E) recessive short

19. By which of the following can movement of materials across animal cell membrances be accomplished?

I. Active transport

II. Diffusion

III, Pinocytosis

(A) I only

(B) II only

(D) I and II only

(E) I,II and III

20. During early development, the embryo of a ci and the embryo of a pig both share many similarities, including gill slits, tails, and a two suggest chickens and pigs most probably

(A) have a common ancestry

(B) use gills for breathing in the early amino fluid

(D) have gill slits for breathing in an emerge as adults

(E) have a two-chambered heart as adults

21. A popular supposition about the extinction of dinosaurs at the end of the Mesozoic Era post that an asteroid smashed into each, causing sucatastrophic environmental changes that the dinosaurs died off in a relatively short time, the changing the cours of evolution. This concept an example of

(A) the theory of gradualism

(B) the theory of punctuated equilibrium

(D) geographic isolation

(E) the Hardy-Weinberg Principle

22. A lipid molecule is composed of glucerol and acid molecules in a ratio of

(A) 1:1

(B) 1:2

(D) 1:4

(E) 1:5

23. Trees grow in which of the following biomes?

I. Tundra

II. Taiga

III. Temperate deciduous forest

(A) I only

(B) II only

(D) I and III only

(E) II and III only

24. Different strata of rock in an undisturbed region are found to contain two different fooils: A and B Fossil A is located in the layer of rock above the layer with fossil B. Which of the following statements is most likely true?

(A) Fossil B is older than fossil A.

(B) Fossil A is older than fossil B.

(D) Fossil B is that of an organism that evolved from fossil A.

(E) Fossil A and B are closely related and evolved from a common ancestor.

25. Of the following, the one that contain the largest number of different types of cells is

(A) mucous membrance

(B) smooth muscle

(D) small intestine

(E) blood

26. Human are similar in structure to apes such as the chimpanzee and the orang-utan. A possible explanation for this similarity is that

(A) humans are descended from apes

(B) apes are descended from human

(D) human and apes had a common ancestor

(E) early humans apes lived in caves

27. Animals that have jointed appendages include which of the following?

I. Spider

II. Crab

III. Snail

(A) I only

(B) II only

(D) I and II only

(E) I,II and III

28. The blood type known as the universal donor is

(A) A

(B) B

(D) O

(E) Rh factor

29. All of the following are function od the skin EXCEPT

(A) protection

(B) sensation

(D) manufacture of vitamin D

(E) exhalation

30. Of the following processes, which one is represented by this equation:

enzymes

6CO₂+12H₂O -------------à C₆H₁₂O₆+6H₂O?

Energy

(A) Fermentation

(B) Lactation

(D) Aerobic respiration

(E) Anaerobic respiration

31. A never cell that transmits impulses from a sense organ to the nervous system is khown as a(n)

(A) sensory neuron

(B) motor neuron

(D) plexus

(E) ganglion

32. The weakness in Darwin’s theory of how evolution occurs was his inability to explain the

(A) mechanisms that produce variation

(B) reasons for overproduction

(D) adaptations of living organisms for survival

(E) inheritance of acquired characteristic

33. Which of the following represents the sequence of bases on the messenger RNA formed from a DNA base sequence of AAC-ATC?

(A) AAG-ATG

(B) AAC-ATC

(D) TTG-TAG

(E) UUT-TUT

34. An increase in the diameter of an oak tree is caused chiefly by the activity of the

(A) vascular ducts

(B) bark

(D) cambium

(E) annual rings

35.What effect does the hydrolytic action of enzymes have on organic molecules?

(A)They are converted to more complex forms.

(B) Their hydrogen-ion concentration is increased.

(D) They become chemically inactive.

(E) They become smaller.

36. The marrow of bones in humans provides

(A) cartilage for the ends of the bones

(B) white fibrous connective tissue

(D) a source of new blood cells

(E) connection between the tendons and ligaments

37. What biological relationship is illustrated by this well-known jingle of the 18^th–century satirical writer Jonathan Swift?

Big fleas have little fleas

Upon their backs to bite ’em.

And little fleas have lesser fleas

And so, ad infinitum

(A) Life in a niche

(B) Abiotic factors

(D) Food guide pyramid

(E) Population in a community

38.Which of the following explains why carnivorous animals depend on green plants for their food?

(A) Carniyores need to achieve a balanced diet.

(B) Only herbivorous animals have grinding teeth.

(D) Carnivores need protection against vitamin deficiency diseases.

(E) Only omnivores are both carnivores and herbivores.

39.Although the island of Madagascar is separated from Africa only by a narrow strait, many plants and animals common on the mainland are unkmown on the island. What principle does this fact illustrate?

(A) Incomplete dominance

(B) Independent assortment

40. Which of the following is indicated by the information on the accompanying graph?

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(A) The rate of enzyme action is directly dependent upon the substrate concentration

(B) The rate of enzyme action increases constantly with an increase in enzyme concentration

(D) Enzym concentration has no effect upon the rate of enzyme action .

(E) When the substrate concentration is increased the enzyme concentration is decreased.

41. When Mendel crossed pea plants that were hybrid for smooth seed from ( smooth is dominant; wrinkled is recessive), he obtained 1,850 wrinkled seeds out of a total of 7,324. Which of the following would be most likely to represent the number of smooth seeds?

(A) 1,850

(B) 3,700

(D) 7,324

(E) 9,174

42. Animals fed vitamin B₁₂ show increased growth. Pure vitamin B₁₂ is extracted from waste materials left in vats in which antibiotics were made. Animals fed on a diet that includes wastes from the antibiotic vats grow faster than those fed only pure vitamin B₁₂ . Which of the following is the most probable explanation?

(A) Waste from the antibiotic vats contain a growth promoter other than vitamin B₁₂

(B) Pure vitamin B₁₂ is not a growth promoter at all

(D) The waste material in the vats contains vitamin B₁₂ that the process does not extract.

(E) Population originally inhabiting the entire area shown on the accompanying diagram has become separated into two population, A and B, by a barrier

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43. If the environment inhabited by population A undergoes severe changes and the environment of population B does not, which of the following will most likely be true about the rate of evolution of population A?

(A) It will be consistently slower than that of population B.

(B) It will consistently faster than that of population B.

(D) It will be slower at first and then faster than that of population B.

(E) It will depend on the rate of evolution of population B.

44. A climax community in North America can exist for a long period of time if it

(A) is host to many pioneer organisms

(B) alters the local elimate

(D) contain a variety of mosses and ferns

(E) contain a mixture of maples, pines, and tall grasses

45. Plankton is composed of

(A) microscopic life

(B) platelets

(D) fish

(E) whales

46. Competition among members of a praire dog population in a given area would probably increase as a result of an increase in the

(A) rate of reproduction of their predators

(B) prairie dog reproduction rate

(D) number of prairie dogs killed by cars on the road

(E) number of secondary consuniers

47. An example of a parasite is

(A) nitrogen-fixing bacteria on the roots of alfalfa

(B) a barnacle growing on back of a whale

(D) a remora fish attached to a shark

(E) the protozoan that causes malaria

48. The thin layer of life surface of the earth, including the biologically inhabited soil, water, and air is known as the

(A) biogeography

(B) biome

(D) biomass

(E) biotin

Question 49-51 refer to the following diagram of paramecium.

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49. Food is digested by

(A) 2

(B) 4

(D) 6

(E) 7

50. Which of the following contains the chromosomes

(A) 3

(B) 5

(D) 7

(E) 8

51. Which of the following permits diffusion of dissolved gases?

(A) 3

(B) 4

(D) 6

(E) 8

Direction : Each set of lettered choices below refers to the numbered statements immediately following it. Choose the one lettered choice that fits each statement and then blacken the corresponding space on the answer sheet. A choice may be used once, more than once, or not at all in each set.

Question 52-54

(A) Left atrium

(B) Left ventricle

(D) Right ventricle

(E) Aorta

52. Receives blood from the lungs

53. Sends blood to the lungs

54. Receives blood from the head

Question 55-57

(A) Test cross

(B) Mutation

(D) Independent assortment

(E) Segregation

55. How haemophilia is inherited

56. Show a gene affecting pigmentation is changed to produce an albino

57. How dark-haired parents with brown eyes have a child with blond hair and brown eyes

Question 58-60

(A) Phototropism

(B) Geotropism

(D) Hydrotropism

(E) Chemotaxis

58. How a plant grows after it has been blown over by the wind

59. How a paramecium reacts to salt

60. How a euglena moves in a partly shaded pool

Part B (Question 61-80)

Question 61-63

In an ecological study of vegetation in a cultivar garden bed that had been neglected for eight week a record was made of the number of weeds that we found in an area measuring a square foot. Twenty-random trials were made and the findings sugmari inTable I by multiplying the totals by 4, the percentage occurrence in 100 trial areas is obtained. The species were then arranged in five groups according to frequency of accurrence, as shown in Table II.

TABLE I

Species

Total Occurrence

In 25 Trials

Poa

Stellaria

Capsella

Senecio

Lamium

Veronica

TABLE II

Group

Percentage Occurrenence

III

0-20

21-40

41-60

61-80

81-100

61. The number of species present in Group II is

(A) 0

(B) 1

(D) 3

(E) 4

62. The least common species classified in Group I

(A) Stellaria

(B) Capsella

(D) Senecio

(E) Veronica

63. From this study it may be concluded that the two most common weeds to be found in tis entire neglected garden bed were

(A) Senecio and Capsella

(B) Senecio and Lamium

(D) Poa and Lamium

(E) Poa and stellaria

Question 64-66

The 24-hour clocks shown below illustrate the effects of different periods of light and dark on chrysanthemum and black-eyed Susan. In I, the long night produces flowering in chrysanthemum only. In II, the short night produces flowering only in black-eyed Susan.

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64. From these observations, which of the following is a reasonable conclusion?

(A) Chrysanthemums bloom in the summer, when night are short.

(B) Chrysanthemums and bloom in the fall, when night are long.

(D) Black-eyed Susans bloom when the nights are long

(E) It is not possible to predict under what condition black-eyed Susans will bloom.

65. To encourage chrysanthemum flowering in July, when the days have more than 12 hours of sunlight an experimenter would

(A) place the plant in a dark room after 11 hours of daylight each afternoon, and then more it outdoors again each morning

(B) place the plant in a dark room at 11 p.m. each night, and then return it outdoors agaun early each morning

(D) place a transparent plastic cover over the plant every morning

(E) cover the plant with an opaque box every night

66. An experimenter desires to get black-eyed Susan to produce flowers in the late fall, when the night are long. Which course of action should he take?

(A) Grow the plant in a hydroponic solution.

(B) Apply a fertilizer that encourages flowering

(D) Expose the plant to artificial illumination for 6 hours daily, beginning at sunrise.

(E) Expose the plant to artificial illumination for 6 hours daily , beginning at sunset.

Question 67-71

There are two forms of the pappered moyh (Biston betularia), one dark in color and one light. Scientists observed that in the industrial area of Manchester England, the originally prominent light from was replaced by the dark from between the years 1848 and 1895. At first, there were only light forms; later, the dark form comprised 98 percent of the total population. A scientist explained this evolutionary change as follows; The moths rest on tree trunks during the day and Through there protective coloration avoid being seen and eaten by insectivorous birds. In the earlier years, before 1848, any dark forms were conspicuous on the light-colored tree trunks and were easily found by birds. With the coming of many factories after 1848, tree trunks became blackned by the soot given off in chimney smoke. Then the dark forms of moths resembled the back ground more closely, while the light forms stood out and were easily seen, and eaten by the birds.

Use the graphs shown on the following page to answer questions 67-69.

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67. Which graph represents the original population of the peppered moth?

(A) 1

(B) 2

(D) 4

(E) 5

68. Which graph represents the moth population after the coming of the factories?

(A) 1

(B) 2

(D) 4

(E) 5

69. The rural area of Dorset , England, has no factories, and the tree trunks are light in color. In a scientific study, equal numbers of the dark and light forms of the moth were released into the area. Which graph represents the percentages of the surviving moths?

(A) 1

(B) 2

(D) 4

(E) 5

70. Which of the following offers the best explanation for the change in moth color after 1848?

(A) Inheritance of acquired characteristics

(B) Gene mutation caused by the soot

(D) Lamarck’s theory of evolution

(E) Ingestion of the soot particles

71. What question would scientists need to answer in order to determine whether the two forms light and dark, of the moth have become different species?

(A) Are the two forms the same size?

(B) Do the dark moths fly more frequently during the day than the light moths?

(D) Can the two forms interbreed?

(E) Do the two forms feed on different food?

Question 72-74

A project was conducted to determine the factors involved in frog hibernation. The effects of reduced temperature on the breathing rate were studied. Graph I was prepared to show the results. Graph II shows the first experiment, the frog attempted to hibernate at 4.4°C. During the second experiment it attempted to hibernate at 12.8°, 11.5°, 10.0°, 6.7°, 5.0°, 2.2°, and 1.1°. The attempts to hibernate included these activities; The frog closed its eyes and expelled air from its lungs; it attempted to dig in at the bottom of the jar as though there were mud there.

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72. From this project, it can be conciuded that

(A) frogs hibernate when the temperature is reduced

(B) as the temperature is lowered, the heatheat is reduced

(D) the breathing rate is reduced as the temperature is lowered

(E) frog stop breathing when they attempt to hibernate

73. The experiment was done a second time for all of the following reasons EXCEPT to

(A) improve on the techniques of the first experiment

(B) check on the first set of results

(D) locate the brain center that controls hibernation

(E) see whether hibernation could br induced artificially

74. At 15°C, the breathing rate

(A) was higher than at 16.6° in Graph I

(B) was lower than at 16.6° in Graph II

(D) was at its lowest point in Graph I

(E) showed an increase in Graph I

Question 75-77

It has been found that the flowering rate of plants is related to the length of daylight. This phenomenon is known as photoperiodism. Some plants are short-day plants; they flower only when they are exposed to short periods of light. Other plants are long-day plants; they produce flowers only when they are exposed to long periods of light.

The graph below shows the annual change in the length of day throughout the year at four latitudes: Miami (26°). San Francisco (37°),Chicago (42°), and Winnipeg (50°), and also the hours of darkness required for three different plants to flower.

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75.The cocklebur plant requires 9 hours or more of darkness ( or 15 hours or less of light), in order to flower. It therefore will flower immediately when it is up to do so in

(A) Miami

(B) Chicago

(D) all cities on March 21

(E) none of these cities

76. The cocklebur will begin to from flower buds in Winnipeg about

(A) March 3

(B) April 3

(D) August 3

(E) January 3

77. The Mary land Mammoth tobacco a short-day plant, forming flowers when the days are 10-12 hours long; it will therefore flower

(A) only in Winnipeg in the middle of the summer

(B) in all the cities except Winnipeg in the middle of the summer

(D) in the middle of the summer in all the cities

(E) very late in the summer in all the cities

Question 78-80

A farmer collected 203 pellets of indigestible remains dropped by barn owls on his farm. He took the pellets to a nearby museum for analysis of the type of food eaten by the owls. The following results were obtained;

429 meadow mice 96 short-tailed shrews

4 lemming mice 1 squirrel

1 pine mouse 5 cottontail rabbits

12 white-footed deer mice 23 unidentified mice

18 jumping mice 5 small birds

21 star-nosed moles 1 Brewer’s mole

78. The most common prey of the barn owls were

(A) white-footed deer mice

(B) jumping mice

(D) meadow mice

(E) lemming mice

79. Which of the following was the only type of non-mammalian prey?

(A) Squirrls

(B) Moles

(D) Rabbits

(E) Shrews

80. On the basis of these findings, the best course of action for the farmer to take would be to

(A) kill all awls as a menace to his chickens

(B) feed poisoned pellets to awls to get rid of them

(D) scare owls away with white mice

(E) inform his neighbours that he now has proof that owls are a great menace to small birds

Answer Key: Practice Test 4

1. (C)

2. (D)

3. (B)

4. (C)

5. (B)

6. (E)

7. (C)

8. (D)

9. (B)

10. (B)

11. (D)

12. (E)

13. (A)

14. (E)

15. (D)

16. (B)

17. (C)

18. (B)

19. (D)

20. (A)

21. (B)

22. (C)

23. (E)

24. (A)

25. (D)

26. (D)

27. (D)

28. (D)

29. (E)

30. (C)

31. (A)

32. (A)

33. (C)

34. (D)

35. (E)

36. (D)

37. (C)

38. (C)

39. (D)

40. (C)

41. (C)

42. (A)

43. (B)

44. (C)

45. (A)

46. (B)

47. (E)

48. (C)

49. (E)

50. (E)

51. (B)

52. (A)

53. (D)

54. (C)

55.(C)

56.(B)

57. (D)

58. (B)

59. (E)

60. (A)

61. (B)

62. (C)

63. (E)

64. (B)

65. (A)

66. (E)

67. (E)

68. (A)

69. (E)

70. (C)

71. (D)

72. (D)

73. (D)

74. (C)

75. (A)

76. (D)

77. (E)

78. (D)

79. (C)

80. (C)

Answer Explained:

1. (C) The diagram show the structural formula of the glucose molecule. A molecule is the smallest part of a substance.

2. (D) Carbon fixation takes place during the dark phase of photosynthesis. A number of intermediate products are formed when, carbon atoms are combine to form C-C bonds, and when hydrogen unites with carbon to form C-H bonds. The first stable product is PGAL (phosphogylceraldehyde), which is then used in the synthesis of glucose.

3. (B) When a wound occurs, the platelets break up and start a series of reaction. Inthe process, one of the dissolves protein in the plasma, fibrinogen, becomes insoluble and turns into threads of fibrin. The red blood cells become entangled in this network, causing a clot to form.

4. (C) In the land-dwelling grasshopper, nitrogenous wastes are largely excreted as acid. Since this substance is very insoluble, little water is used to carry it in solution . Instead, it is removed in solid crystal form by the Malpighian tubules, which open into the digestive system. The wases are then climinated through the anus along with undigested food materials. This method of excretion server as a water-conservation mechanism for certain land-dwelling organisms.

5. (B) Acetylcholine is produces along the length of a neuron and plays a part in the transmission of a neuron impulse. It is also formed in a synapse.

6. (E) When double fertilization occurs within the ovule, one part develops into an embryo, and the rest becomes the food and covering. The matured ovule becomes the seed.

7. (C) Red blood cells receive their color from the haemoglobin in them; chloroplasts are green because they contain chlorophyll.

8. (D) During digestion, the nutrients of food are digested to simple, soluble form, and can then diffuse into the bloodstream to be carried to the cells of the body.

10. (B) These animals have changed since the time of their common ancestor, but they still retain enough of the same genes for their forelimbs to be similar in structure.

11. (D) Bean leaves also have a network of veins.

12. (E)In a simple reflex, the sensation is received at a receptor in the skin, and the impulse travels along a sensory neuron to the spinal cord. It then crosses a synapse and enther an interneuron. It passes out across another synapse and enters a motor neuron where it travels along to stimulate an effector, a muscle, to contract and pull the finger back from the sensation, such as a flame.

13. (A) The roots of the plant contain xylem and phloem tissue which extend up through the stem into the leaves. Xylem transports water and minerals up to the stem and leaves. Phloem transports manufactured food from the leaves to other parts of the plant.

14. (E) All the animals are mammals, with microscopic ova having practically no stored food, except the sparrow, which has relatively large eggs (ova) containing a large amount of stored food.

15. (D) The possible results are:

Phaces

16. (B) In myxedema, there is an underproduction of thyroxin, resulting in a reduced basal metabolism rate.

17. (C) When hybrids are crossed, the results are:

Phaces

18. (B) In pea plants, tall is dominant to short. Tall pea plants a recessive gene, and so are heterozygous tall. This can be shown as follows:

19. (D) During active transport, the cell uses energy to move soluble materials across cell membranes, from a region of low concentration to a region of high concentration. By diffusion, molecules of soluble substances pass through cell membranes from a region of high concentration to a region of low concentration; this is passive transport since the cell does not use energy. In pinocytosis, relatively large particles, such as protein, are engulfed by pockets of the cell membrane.

20. (A) The similarty of these embryos indicates that these animals are most probably descended from a common ancestor and that they still have some similar genes in their early development. The gill slits will disappear, as wil the tail in the chicken embryo; the two-cham-bered heart will develop into four chambers in both animals.

21. (B) The theory of punctuated equilibrium proposed by Eldridge and Gould holds that some species remain unchanged for long periods. Then there are short periods during which new species are rapidly formed. It differs from Darwin’s theory, which is based on the concept of gradualism, in which organisms change gradually during the ages.

22. (C) A lipid molecule consists of a glycerol molecule bonded to three fatty acid molecules.

23. (E) Tundra is the treeless region in the Arctic Zone, where the underlying part of the soil is permanently frozen.

24. (A) Strata of rock were originally formed from layers of sediment that were deposited under water and become sediment together by pressure over the ages. Thus, sand turned into sandstone, and shale was formed from deposits of clay. The lower strata were laid down first, so any fossils found in them would be older than fossils above them that became embedded in upper strata later on.

25. (D) The small intestine is an organ composed of various types of tissues, including all those mentioned in the others, choices, that work together.

26. (D) studies of the DNA of humans and apes have shown that the sequence of nucleotides is very similar in both species. Other similarities in structure and biochemical composition have led scientists to speculate that humans and apes are derived from a common ancestor.

27. (D) The spider and the crab are members of Arthropoda phylum, whose characteristic include jointed appendages, an exoskeleton chitin, and segmented bodies. The snail classified as a mollusc; it is a soft-bodied an mal, with a muscular foot and a mantle the secretes the shell.

28. (D) Blood of the O type may be safely given in transfusion to people who have other blood groups.

29. (E) The skin does not exhale air ; this is done only through the lungs.

30. (C) Photosynthesis takes place within the chloroplasts of a green plant. Carbon dioxide (CO₁) and water (H₂O) are taken in. Chlorophyll becomes activated by light energy and decomposes the water molecules, releasing oxygen (O₁) as a gas; this occurs during the light phase. It is followed by a dark reaction during which carbon fixation takes place. A number of enzymes combine carbon dioxide and hydrogen atoms to form a six-carbon sugar, glucose (C₆H₁₂O₆).

31. (A) A sensory neuron is also known as an afferent neuron.

32. (A) Darwin’s theory of natural selection was published after many years of careful observation and study. He come to his conclusions after he had accumulated much evidence to support them, mostly based on the observations he him self had made. He was frank to admit that there were aspects of evolution he could not explain because he did not have enough data for a full understanding, for example, how variations were caused, and how life originated on earth.

33. (C) RNA contains a uracil (U) base instead of a thymine (T) base, which lines up with adenine (A). Cytosine (C) lines up with guanine (G). The adenine (A) of RNA lines up with the thymine (T) of DNA.

34. (D) Cambium consists of actively dividing cells that differentiate into xylem, phloem, and additional cambium cells, adding to the diameter of the trunk

35. (E) A complex chain of organic molecules may be broken down during the process of hydrolysis. Water is added while enzymes break apart the bond between the molecules, and give rise to individual smaller molecules. Example: The disaccharide, maltose, is hydrolyzed by the enzyme maltase into the simpler molecules of glucose.

36. (D) Red blood cells and white blood cells are manufactured in the marrow of bones. Red blood cells form special round disc cells that lose their nuolei before they enter the bloodstream; they also contain hemogiobin, which gives them their red color .

37. (C) A food chain represents the different links along which food passes from one organism to another. The various links can be identified as; producers ( green plants) which make food; primary consumers ( herbivores) which eat green plants; second and third, order, consumers ( carnivores) which break down the wastes and dead bodies of producers and consumers.

38. (c) Without green plants there would be no food. Carnivorous animals eat herbivorous animals, which depend on green plants for their food .

39. (D) Because of the water barrier, the plants and animals on the mainland were prevented from migrating to the islands and interbredding. Therefore, changes that took place in one area were not transmitted to the other area. Consequently, over a long period of time, these changes became accenturated, making the mainland and islanad species quite different from each other. This illustrates the principle that evolution in isolated populations proceeds in different directions.

40. (C) The graph shows that the relative rate of the enzyme activity rises as the enzyme concentration increases until the concentration is about 7. After that point, the relative rate of the enzyme activity levels off at about 35, and remains the same.

41. (C) When hybrids are crossed, the results are in a ratio of 3 dominant :1 recessive. There would therefore be about three times as many smooth seeds as wrinkled seed (1,850 * 3=5,550, or approximately 5,474).

42. (A) Waste from antibiotic vats contains many substances. One of them, vitamin B12, is known to increase the growth of animals. Evidently there must be an additional growth promoter other than vitamin B12 in the waste.

43. (B) If there is a drastic change in the environment of population A, many organisms athat are not dapted to the new conditions will die out. The few that are adapted will survive and will pass heir genes on to the next generation. By natural selection over a period of time, organisms that are fit for the new environment will continue to survive, increasing the gene frequency for the favourable characteriscis. This may lead to evolutionary changes in population A.

44. (C) In a climax community, each species reproduces at a rate that maintains inself at the same number from year to year. There is an equilibrium between the living things in it and it may continue indefinitely . Examples of this include maple-beech forest in northeastern United States, pine forests in New Jersey, and tall grasses on the prairies.

45. (A) Plankton is the floating mass of microscopic life composed of algae that make their own food by photosynthesis , as well as protozoa and minute invertebrates that feed on the algae.

46. (B) As the prairie dog reproduction rate increase there will be more animals depending on the available food in the given area. This will inevitably increase the competition them for the food supply.

47. (E) Plasmodium, the protozoan that enters the body through the bite of the Anopheles mosquito, invades and destroys the red blood corpuscles of its host, it is the deadly parasite

48. (C) The biosphere includes all the living thing dwelling at or near the earth’s surface. I also thought of as including a system of relationships between the living things and materials and energy surrounding them.

49. (E) Food Vacuole

50. (E) Micronucleus

51. (B) Cell membrane

52. (A) The pulmonary veins bring oxygenated from the lungs to the left atrium of the heart.

53. (D) When he right ventricle contracts, it supply blood into the pulmonary arteries, which it to the lungs.

54. (C) The right atrium receives blood from the circulation through the superior vena (From the head and upper part of the body the inferior vena cava (from the lower part of the body).

55. (C) Haemophilia is inherited as a sex-linked recessive trait.

56. (B) The change in a normal gene for pigment to the albino condition is inherited and is known as a mutation

57. (D) Hair colour and eye colour are traits that are inherited independently of each other.

58. (B) The stem grows upward, this is negative geotropism.

59. (E) The paramecium moves away from salt, illustrating negative chemo taxis.

60. (A) The euglena moves toward the lighted side, illustrating positive photropism.

61. (B) Only Senecio is present. Ten multiplied by 4 gives a percentage occurrence of 40 % for Group II.

62. (C) Only one example of Lamium was found in 25 trials.

63. (E) Poa and Stellaria were found to occur in every one of the 25 trails, making them the most numerous.

64. (B) This is an example of photoperiodism. Chrysanthemums require a long period of the darkness in order a flower. In the fall, when the hours of daylight are less than 12-13, such short-day flowers will bloom.

65. (A) These actions would reduce the exposure of the plant to light, and increase the length of the dark period. Since chrysanthemum is a long-night plant, it would be stimulated to flower in july.

66. (E) This action would reduce the exposure of the plant to light and reduce its exposure to darkness. Since black eyed susan is a short night plant , it would be stimulated to flower.

67. (E) In the earlier years before the development of factories, the tree trunks were light in color. The protective coloration of the light-colored moths allowed them to escape the notice of insectivorous birds and to multiply freely. On the other hand, dark moths were conspicuous and more easily found by the birds. Graph 5 Shows a far greater number of the light-colored moths.

68. (A) Once the factories were established, the soot given off by the chimney smoke became deposited on the tree trunks, blackening thm. The dark moths resembled this background and escaped the attention of the birds. The light moths, however, were conspicuous and were readily eaten by the birds. Graph I shows a predominance of dark moths.

69. (E) The light moths blended into the background of the light-colored tree trunks and escapes detection by the birds. The dark moths stood out against this background and were eardily seen and eaten birds. Graph shows the relative percentages of the survivors.

70. (C) The favourable variation was the color of the moths that resembles the color of the tree trunks, which had become dark from soot. These moths could not be readily seen by the birds. As a consequence, they escaped detection and survived. This natural selection did not favour the light-colored moths which stood out against the color of the tree trunks, and they died out in larger numbers.

71. (D) A species is a closely related group of organisms that are similar in sturctur and can interbreed. If the two forms could not interbreed, they would be considered different species.

72. (D) The graphs show that the number of breaths per minute decreased with the reduction intemperature.

73. (D) All of the items except (D) represent good scientific procedure.

74. (C) At 15°C, the breathing rate in Graph II was 50 breaths per minute. In Graph I , at 16.6°C. It was only 44. In Graph II, it was 46 at 16.6°C.

75. (A) Since the day length in Miami is less than 14 hours throughout the summer, the cocklebur plant has more than 9 hours of darkness daily, and so can flower as soon as it is ripe to so . In other parts of the country it will begin to flower when the days become short enough for this amount of darkness to set in daily.

76. (D) In early August, the day length in Winnipeg becomes reduced to 15 hours, and then proceeds to get shorter. This exposes the cocklebur plants to 9 or more hours of darkness, and they begin to form flower buds.

77. (E) Toward the end of September, all of the cities begin to have 12 hours or less of daylight. The tobacco plant therefore begins to produce flowers after that date.

78. (D) There were 429 pellets of meadow mice.

79. (C) Birds are not mammals; all the other choices are mammals.

80. (C) The owl is a very useful part of the farm environment since it destroys animals that eat the farmer’s grain and his crops. The evidence indicates that owls rarely go after birds, but live mainly on rodents and other small mammals.

11^THDIAGNOSTIC TEST

PART A

Direction : Each question or incomplete statement below is followed by five possible answer or completion, lettered A-E. Choose the answer that is the best in each case. Fill in the corresponding oval on your answer sheet.

1. In a climax community, which of the following will be observed?

(A) The nitrogen cycle ceases to be important for primary producers.

(B) There are no changes in seasonal population size in the community.

(D) There is no loss of energy from one trophic level to the next

(E) There is only one species of primary producer

2. Air entering the hungs of a tracheotomy patient through a tracheotomy ( a tube inserted directly into the trachea) is colder and their than normal, which often-causes lung crusting and infection. This occurs primarily because the air

(A) Enters the respiratory system too rapidly to be filtered

(B) Is not properly humidified by the larynx

(D) Does not flow past the mouth and tobue

(E) None of the above

3. Smooth muscle develops from which of the following germ layers?

(A) Endoderm

(B) Mesoderm

(D) Ectoderm

(E) None of the above

4. What is the function of a lysosome’s membrance?

(A) It isolates an acidic environment for the lysosome’s hydrolytic enzymes from the natural pH of the cytoplasm.

(B) It is continuous with the nuclear membrance, thereby liking the lysosome with the endoplasmic reticulum.

(D) The cytochrome carriers of the electron transport chain are embedded within it.

(E) It separates the nucleus from the cytoplasm.

5. Which of the following statements regarding evolution is true?

(A) Certain phenotypes are more fit in certain environments than others.

(B) Natural selection creates new alleles.

(D) Mutation always affect the fitness of art organism.

(E) All of the above

6. For the following organisms, which follows the correct sequence of evolution through time, starting with the organism that existed first?

(A) Sponge, flatworm, chordate, mollusc

(B) Flatworm, mollusc, sponge, chordate

(D) Mollusc, sponge, flatworm, chordate

(E) Flatworm, sponge, chordate, mollusc

7. A culture of algae is inoculated with small numbers of two different species of protozoan ciliates, protozoan A and C that feed on the algae. Protozoan A replicates asexually once every hours and protozoan C replicates asexually once every 1.5 hours under these condition, as long as the algae is not limiting. Which of the following is most likely to be observed.

(A) The protozoans will evolve to have a mutualistic relationship.

(B) Both population of protozoans will increase in size initially, but then protozoan, C will the off them the culture.

(D) The algae will die off from the culture due to overfeeding.

(E) Protozoan C will evolve to replicate more rapidly.

8. Oogenesis the process by which

(A) Primary oocytes produce sperm

(B) Primary oocytes produce eggs

(D) The egg is released from the ovary

(E) Star fish regenerate limbs

9. An individual that has only one X chromosome is genotyically XO. This person

(A) Cannot survive

(B) Wil have immature, ambiguous( both male and female) reproductive system

(D) Does not produce steroid hormones

(E) None of the above

10. Inthe process of fat emulsification, bile salt make fats more susceptible to the action of lipases by

(A) Transporting fat globules to the region of lipase activity

(B) Increasing the surface area of the fat globules

(D) Lowering the pH of the small intestine

(E) None of the above

11. There is a recessive allele for a gene that made people more susceptible than normal to smallpox. Only homozygous recessive people display this trait; heterozygotes are indistinguishable from homozygous dominant people, with normal resistance to smallpox. After the point at which the smallpox virus was eliminated from the earth, which of the following occurred to the allele frequency for the allele that caused smallpox susceptibility?

(A) The allele declined in frequency for several generations and then disappeared

(B) The allele remained at a constant frequency in the gene pool.

(D) The number of homozygous recessive people remained the same, but the number of heterozygous people increased for several generations

(E) None of the above

12. Brain cells of the housefly Musca domestica have 6 pairs of chromosomes. Therefore, it can be concluded that

(A) The fly’s diploid number is 24

(B) The fly’s diploid number is 12

(D) The fly’s diploid number is 6

(E) The fly’s diploid number is 24

13. A snake eats frogs, which eat grasshoppers. The snake is an example of a

(A) Primary consumer

(B) Secondary consumer

(D) Tertiary consumer

(E) Decomposer

14. Which of the following is an example of a scavenger?

I. Fungi

II. Valutre

III. hyena

(A) I only

(B) II only

(D) I and III

(E) II and III

15. A black male mouse (I) is crossed with a black female mouse, and they produce 15 black and 5 white offspring. A different black male mouse (II) is crossed with the same female, and the offspring from this mating are 30 black mice. Which of the following must be true?

(A) The female mouse is homozygous

(B) Male mouse II is heterozygous

(D) All the progeny of mouse II are homozygous.

(E) All three mice are homozygous.

16. A difference between fate and carbohydrates is that

(A) Carbohydrates are always steroids

(B) Carbohydrates have a H:O ratio of 2:1

(D) Fats have a H:O ratio with much more oxygen than hydrogen

(E) Fats always contain nitrogen

17. Water diffuses into and out of cells via

(A) Carrier proteins

(B) Symport system

(D) Osmosis

(E) Active transport

18. Which of the following statements illustrates the principle of induction during vertebrate development?

(A) The presence of a notochord beneath the ectoderm result in the formation of a neural tube.

(B) A neuron synapses with another neuron via a neurotransmitter

(D) Secretion of TSH stimulates the secretion of the hormone thyroxine

(E) None of the above

19. What is the correct sequence of events in the development of the embryo?

(A) Morulaà cleavageà blastulaà gastrula

(B) Cleavageà morulaà blastulaà gastrula

(D) Blastulaà cleavageà gastrulaà morula

(E) Morulaà blastulaà cleavageà gastrula

20. Members of a class are more alike than members of

(A) An order

(B) A phylum

(D) A species

(E) A family

21. Pancreatic lipase is involved in the digestion of

(A) Starch

(B) Protein

(D) Cellulose

(E) Nucleic acids

22. A population of horses is split into two population by a new riverbed that forms after a flood. After many generations, the river changes course and the populations mix again. Which of the following indicates that the two population have formed two

(A) The population refuse to cross the dry riverbed to interbreed.

(B) The populations mix and mate and offspring are produced, although they are sterile.

(D) Both populations are primary consumers.

(E) The horses interbreed, but the offspring are shorter than either of the parents.

23. The mouse is known as Mus musculus. The Mus is the

(A) Phylum

(B) Class

(D) Genus

(E) Species

24. Albinos have a genotype of aa, white all other members of population are either AA or Aa. The offspring of a cross between a heterozygous male and albino female would be

(A) 100% albino

(B) 100% normal

(D) 25% normal, 75% albino

(E) 75% normal, 25% albino

25. Which part of cellular respiration directly produces a pH gradient during the oxidative metabolism?

(A) Glycolysis

(B) Anaerobic respiration

(D) Electron transport chain

(E) None of the above

26. Which of the following lions has the greatest fitness

(A) A male that dies young and leaves three cubs that are raised by an unrelated female

(B) A female that raises four of her cousin’s young

(D) A female that raise five young of an unrelated female

(E) A male that has one cub with two different females

27. The first organisms on Earth were thought to be

(A) Autotrophs

(B) Chemosynthetic

(D) Oxygen producing

(E) Photosynthetic

28. Maple trees, apple trees, orchids, and palms are examples of

(A) Gymnosperms

(B) Bryophytes

(D) Chlorophytes

(E) Rhodophytes

29. Molds and yeast are classified as

(A) Rhodophytes

(B) bryophytes

(D) ciliates

(E) flagellates

30. in humans brown eyes are dominant over blue eyes. In the cross of BB x bb, what percentage of the offspring will have brown eyes

(A) 75%

(B) 50%

(D) 100%

(E) 25%

31. In humans a normal sperm must contain

I. An X chromosome

II. 23 chromosomes

III. A Y chromosome

(A) I only

(B) II only

(D) I and II

(E) II and III

32. Which of the following are bilaterally symmetrical?

(A) Planaria

(B) Roundworms

(D) Arthropods

(E) All of the above

33. In a small population of an endangered desert rodent, which of the following poses a concern for the future of the species?

(A) The frequency of mutation increases in small population.

(B) Natural selection cannot occur in a small population.

(D) There is a lack of natural resources in the desert.

(E) Recessive alleles become homozygous more frequently in small population.

34. Examples of parasitism include all of the following EXCEPT

(A) Bird and rhinoceros

(B) Virus and host cell

(D) Tuberculosis bacteria and man

(E) Flukes and fish

35. Meiosis differs from mitosis in that

I. Two cell divisions take place

II. DNA replicates during interphase

III. Haploid cells are produced from diploid cells

(A) I only

(B) II only

(D) I and III

(E) I,II and III

36. Stomata in plant leaves close at night to prevent the loss of

(A) O₂

(B) H₂O

(D) Energy

(E) Cjlorophyll

37. When calcium binds troponin in muscle cells, the binding site for which of the following is exposed?

(A) Tropomyosim

(B) Myosin

(D) ADP

(E) Pi

38. All organisms utilize

(A) CO₂

(B) A triplet genetic code to produce proteins

(D) ADP as cellular energy

(E) Membrane-bound organelles

39. In fruit flies, the gene for wing type is located on an autosomal chromosome. The allele for wild-type wings is dominant over the allele for vestigial wings. If a homozygous dominant male fly is crossed with a female with vestigial wings, what percentage of their female with progeny are expected to have wild-type wings?

(A) 0%

(B) 25%

(D) 75%

(E) 100%

40. Scientists studied a pond and found water skimmers and minnows. Fifteen years later the pond had filled in, resulting in swampy land; frogs and snakes were prevalent. This is a result of

(A) Predation

(B) Succession

(D) Natural chsaster

(E) Global warming

41. Damsel flies and dragonflies can live in the same ecosystem because

(A) They occupy different niches

(B) They are commensal

(D) Dragonflies have stronger wing muscles than damsel flies

(E) They mate at different times of the year

42. Legumes are good for the soil because

(A) Deer won’t eat them

(B) They are photosynthetic

(D) Animals convert them energy

(E) None of the above

43. If the DNA sequence is 5TACAGA3, then the complementary mRNA sequence is

(A) 3UCUAUG5

(B) 3TACAGA5

(D) 3UACAGA5

(E) 3ATGTCT5

44. Sexually reproducing species can have a selective advantage over asexually reproducing species because sexual reproduction

(A) Is more energy efficient

(B) Allows for more genetic diversity

(D) Always decreases an offspring’s survival ability

(E) Can occur in any climate

45. The genes encoding for eukaryotic protein sequences are passed from one generation to the next in

(A) Other proteins

(B) rRNA

(D) mRNA

(E) DNA

Questions 46-50 refer to the following figure

Phaces

46. Structure 1 is known as the

(A) Glomerulus

(B) Bowman’s capsule

(D) Loop of Henle

(E) Distal convoluted tubule

47. Structure 3 is where

(A) Urine is concentrated

(B) Almost all glucose and amino acids are reabsorbed

(D) Blood is oxygenated

(E) The renal artery flows in

48. ADH acts on structure

(A) 4

(B) 5

(D) 7

(E) 8

49. The oegan the depicted structure is a part of is involved in

(A) Digestion

(B) Cellular respiration

(D) Digestion of lipids

(E) Maintenance of the heatbeat

50. Which structure is part of the circulatory system?

(A) 1

(B) 2

(D) 4

(E) 5

Question 51-54 refer to the following figure:

Phaces

51. At which site does digestion of starches begin?

(A) 1

(B) 2

(D) 4

(E) 5

52. Structure 4

(A) Produces bile

(B) Stores bile

(D) Secretes bicarbonate

(E) Secretes HC1

53. Which structure is primarily responsible for water absorption during digestion?

(A) 5

(B) 6

(D) 8

(E) 9

54. Which structure has both exocrine and endocrine function?

(A) 5

(B) 6

(D) 8

(E) 9

PART B

Each set of choices A—E below should be compared to the numbered statements that follow it. Choose the lettered choice that best matches each numbered statement. Fill in the correct oval on your answer sheet.Remembar that a choice may be used once, more than once, or not at all in each set.

Question 55-58:

(A) Growth hormone

(B) Oxytocin

(D) Aldodterone

(E) Glucagon

55. Increases uterine contraction during child birth

56. Stimulates the release of glucose to the blood

57. Induces water resorption in the kidneys

58. Prepares the uterus for implantation of the fertilized egg

Questions 59-61

Phaces

59. The method of respiratory gas movement of a bacteria

60. The circulatory system of a human

61. The circulatory system of a segmented worm

Question 62-65

(A) Nucleus

(B) Endoplasmic reticulum

(D) Gogl apparatus

(E) Lysosome

62. Membrance-bound convoluted organelle that is the site of synthesis of secreted proteins

63. Membrance-bound organelle full of hydrolytic enzymes

64. Membrane-bound organelle that contains the chromosomes

65. This consists of RNA and proteins and helps to translate mRNA during polypeptide synthesis

Question 66-68

(A) mRNA

(B) rRNA

(D) DNA

(E) Nucleolus

66. Site of rRNA synthesis

67. Product of transcripyion, encoding translated proteins

68. Bins specific amino acids and carries then to the ribosomes during protein synthesis

Question 69-71:

(A) Natural selection

(B) Adaptive radiation

(D) Migration

(E) Parallel evolutyion

69. Differential survival based on variations in phenotypes

70. Production of several different species from a common ancestor

71. Appears useless but had an ancestral function

Question 72-75:

Phaces

72. Building block of DNA or RNA

73. Building block of proteins

74. Lipid

75. Carbohydrate

PART C

Each of the following sets of questions is based on a laboratory or experimental situation. Begin by studying the description of each situation. Next, choose the best answer to each of the questions that follow it. Fill in the corresponding oval on your answer form.

Question 76-79 refer to the following paragraph:

All birds and mammals are able to maintain relatively constant body temperature. These animals have evolved thermoregulatory mechanisms that help them to adapt to their environments.One such mechanism is to regulate the metabolic rate. A plot of the rate of oxygen consumption versus body weight for various mammals reveals that metabolic rate is inversely proportional to body weight ( see tigure). However, metabonic rate and the iratisrer of heat to the environment are directly proportional to the surface area-to-volume ratio than a horse, which means that the shrew generates more internal heat to the environment. This makes it especially difficult for small animals to maintain a constant body temperature in cold weather.

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76. Small animals such as penguin chicks will huddle together when it is cold outside. The most likely explanation for this is that

(A) Huddling decreases the effective surface area-to-volume ratio and decreases the loss of body heat

(B) Huddling increases the effective surface area-to-volume ratio and increases the loss of body heat

(D) Huddling is an instinct in penguin chicks

(E) Baby penguins huddle following imprinting

77. A mechanism mammals have developed to dissipate excess heat in hot weather is

(A) Huddling

(B) Sitting in the shade

(D) Burrowing

(E) None of the above

78. Which of the following is most likely true of an animal that must keep all of its vital organs at approximately the same temperature?

(A) It could not survive in a desert environment.

(B) It sweats excessively and becomes dehydrated in hot weather.

(D) It must always have a large supplyof water.

(E) It will be found only on the tundra.

79. Which of the following animals has the highest metabolic rate?

(A) Horse

(B) Dog

(D) Flying squirrel

(E) Cactus mouse

Question 80-83 refer to tye following experiment:

E. coli is a bacteria that can be used to study a variety of mechanisms. In this experiment, one wild type and four mutant trains were tested for their ability to grow in either minimal media or media that was supplemented with various amino acids.

Supplement

None

Arginine

Wild type

Strain 1

Strain 2

Strain 3

Strain 4

Supplement

Threonine

Histidine

Wild type

Strain 1

Strain 2

Strain 3

Strain 4

A (+) sign indicate growth and a (-) sign indicates

80. Based on the table, strain 2

(A) Cannot produce arginine

(B) Cannot produce threonine

(D) Cannot produce glycine

(E) Can produce all amino acids

81. Which amino acid(s) does strain 3 NOT need from the environment to grow?

(A) Arginine and histidine

(B) Threonine and histidine

(D) Arginine and threonine

(E) Threonine only

82. The mutation in strain 1 that renders in incapable of growing without arginine occurs in

(A) DNA

(B) mRNA

(D) the anticodon region of the tRNA

(E) rRNA

83. the mutation in strain 4

(A) reners it dormant

(B) does not affect its ability to synthesize amino acids

(D) is identical to that in strain 1

(E) none of the above

The following graphs depict growth inbacteria under a variety of different conditions with increasing numbers of bacteria on the x-axis and increasing time on the x-axis.In these conditions, the bacteria multiply at the fastest possible rate. The following graph depicts what occurs if bacteria are added to rich broth:

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Use these graphs to answer questions 84-86

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84. which graph shows what happens when you introduce a bacteriophage that lysesthe bacteria six hours after they enter the wxponential growth phase?

(A) 1

(B) 2

(D) 4

(E) 5

85. Which graph describes what happens when you introduce very minimal nutrients for the first six hours, then add surplus nutrients?

(A) 1

(B) 2

(D) 4

(E) 5

86. Which graph shows growth in rich media with additional nutrients added?

(A) 1

(B) 2

(D) 4

(E) 5

In her experiment to determine where the C,H, and O come from when plants produce carbohydrates, a scientist grew plants in the presence of variety of radioactive compounds and used a Geiger counter to determine whether the starch produced by the plants was radioactive.

Molecule Radioactive Starch

Expr. 1 ¹⁴CO₂ +

Expr. 2 H₂¹⁸O -

Expr. 3 C¹⁸O₂ +

Use this data to answer question 87-88.

87. The source of oxygen in carbohydrates produced by plants is

(A) CO₂

(B) H₂O

(D) None of the above

(E) All of the above

88. The oxygen released from the plant comes from

(A) CO₂

(B) H₂O

(D) None of the above

(E) All of the above

89. If a plant utilized H₂SO₄ instead of water, the plant would release

(A) CO₂

(B) H₂O

(D) SO₄²

(E) None of the above

90. Which compound captures light energy in plants?

(A) O₂

(B) CO₂

(D) Chlorophyll

(E) None of the above

91. The light reaction of photosynthesis occurs in the

(A) Stroma

(B) Thylakoid membranes

(D) Nucleus

(E) Ribosomes

92. The Calvin cycle

(A) Does not use light directly

(B) Occurs in the cytopiasm

(D) Produces ATP none of the above

A study of a meadow yielded the following data

Organisms

Number

Hawk

Various bird

Spiders

Insects

Shrubs and other plants

500

3,000

5,000

Use this data to answer question 93-95.

93. Which organisms are the primary consumers?

(A) Hawks

(B) Birds

(D) Insects

(E) Shrubs

94. Which type of organism is not represented?

(A) Primary producer

(B) ....consumer

(D) Primary consumer

(E) Decomposer

95.which of the following is a correct pyramid of biomass?

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Answer Key

1. C

2. C

3. B

4. A

5. A

6. C

7. B

8. B

9. C

10. B

11. B

12. D

13. D

14. E

15. C

16. B

17. D

18. A

19. B

20. B

21. C

22. B

23. D

24. C

25. D

26. A

27. C

28. C

29. C

30. D

31. B

32. E

33. E

34. A

35. D

36. B

37. B

38. B

39. B

40. B

41. A

42. C

43. C

44. B

45. E

46. A

47. B

48. E

49. C

50. A

51. A

52. B

53. D

54. B

55. B

56. B

57. E

58. C

59. D

60. E

61. B

62. B

63. E

64. A

65. C

66. E

67. A

68. C

69. A

70. B

71. C

72. B

73. C

74. A

75. D

76. A

77. C

78. C

79. E

80. B

81. D

82. A

83. B

84. B

85. E

86. C

87. A

88. B

89. D

90. D

91. B

92. A

93. D

94. E

95. B

Answer and explanations

1. (C) A climax community is an ecological system in which the population and the way they relate to each other remain the from one generation to the next. The community is stable in its composition because the population that live there affect the physical environment and each other in a way that promotes the continuance of the same population. All living organisms need nitrogen, making the nitrogen cycle a part of any ecosystem ((A) is wrong). The fact that a climax community is stable does not mean there is no variation in population size between seasons, but that every generation replaces the existing one in the same pattern of ecological interactions((B) is wrong ). There is always loss of energy between trophic levels, since organisms need to burn energy to live ((D) is wrong ). There might be a primary producer ( plants, algae, cic ) that predominates in a climax community, but this is not necessarily true.

2. (C) When a patient breathes through a tracheotomy, the air entering the respiratory system bypasses a very important area--- the nasal cavities. In a normally breathing individual, the extensive surface of the nasal passageways warm and almost completely humidify the air, and particles are filtered out by nasal air turbulence. Since the air reacping the lungs tracheotomy patient has not been warmed or humidified, lung crusting and infection often result (B) and (D) are wrong because the mouth and larynx are much less effective at humidification.

3. (B) The endoderm develops into the lungs, the gastrointestinal tract, and the linig of the bladder. Ectoderm develops into the brain and nervous system, the lens of the eye, the inner ear, hair, nails, sweet glands, the lining of the mouth and nose, and the skin. The mesoderm becomes everything else, including the musculoskeletal system, the reproductive system, the circulatory system, and the kidneys.

4. (A) The lysosome acid has an acidic interior to enhance the activity of lysomal membrane separates the acidic interior of the lysome from the rest of the cell which has a netural pH. The other responses do not involve functions of the lysomal membrane.

5. (A) in Darwin’s theory of natural selection, some organisms in a species have variations in traits that give them an advantages over other members of the species. These adaptations enable these organisms and their offspring to survive in giving them greater fitness.

6. (C) on an evolutionary scale, sponges developed first, followed by flatworms, then mollusks and finally chordates.

7. (B) When two population are in direct competition for the same resource, one population will compete more effectively and will, with time force out the other population. This is particularly true with the relatively short time spans and restricted that B is the best answer. While resources are not limiting, both population will grow. When they compete, the protozoan that reproduces faster, Protozoan A, will out-compete Protozoan C and cause Protozoan C to die out. (A) is wrong--- the relationship between these population is a competitive one, and there is no reason to believe that this relationship will reverse itself to one in which both populations benefit. There is little an algae can do to escape predation ((C) is not the best choice). The populations of predator and prey are likely to reach an equilibrium state which is more or less stable. If the predator population increases and eats more of the prey, as the prey population decreases, the predator will decreases as well. Predators rarely hunt a prey to extinction ((D) is wrong). It is also unlikely that protozoans will be able to evolve so rapidly as to change a fundamental property in a few generations ((E) is wron).

8. (B) Oogenesis is the process whereby primary oocytes undergo meiosis to produce one egg ( or ovum) and two or three polar bodies.

9. (C) A Tumer’s female has the genotype XO; she carries only one X chromosome, has underdeveloped ovaries, and is sterile but is female in appearance. These individuals are often shorter than normal and may have varying degrees of mantal development problems.

10. (B) Bile salts act like detergents to break fat globules into smaller spheres. Emulsification, which occurs via the detergent action of bile salts, increases the surface area of fat globules exposed to the lipases. Since lipases can attack only these surfaces and not other parts of the fat globules, the action of bile salts greatly enhances the ability of lipase to act on fats.

11. (B) When an allele is harmful, as this one would be, it will be selected against. In this case, the allele is recessive and is only expressed in the homozygous recessive people, with heterozygotes as carriers. The homozygous recessive people will be selected against, and the allele frequency in the population will decrease slowly over time as long as the selection pressure is maintained. Once the virus, the allele frequencies will remain constant, unless some other selection pressure affects the allele ((B) is correct).

12. (D) If there are six pairs of chromosomes in a diploid cell, there are a total of 12 chromosomes in a 2n cell, and the haploid cell would have half that number; n=6.

13. (D) Grasshoppers are primary consumers ( they eat plants ). The frog that eats these herbivorous insects is the secondary consumer, while the snake that eats the frogs is a tertiary consumer.

14. (E) A scavenger eats animals that have already been killed; typically, it is incapable of hunting. Vultures are scavengers, while fungi are saprophytic, decomposing dead plant material. Hyenas also act as scavengers, though they also hunt on occasion.

15. (C) In the cross of Mouse I with female, the ratio of the offspring phenotypes is 3:1, indicating a Bb x Bb cross with BB and Bb animals black and bb animal is Bb. In the second cross of mouse II and the female mouse, 100 percent of the offspring are black. Hence Mouse II must be homozygously dominant.

16. (B)Carbohydrates, including glucose, starches, or cellulose, have a H:O ratio of 2:1. Fats, in contrast, have a H:O ratio with more hydrogen than oxygen.

17. (D) Osmosis is defind as the diffusion of water through membranes from an area of lesser solute concentration to an area of greater solute concentration.

18. (A)In terms of vertebrate development, induction is defined as the process by which a particular group of cells. (A) is an example of induction: The group of cells that forms the notochord induces the formation of the neural tube. Other examples of induction in vertebrate development include the formation of the eyes, in which the optic vesicles induce the ectoderm to thicen and form the lens placode, which induces the opyic vesicle to form the optic cup. This in turn induces the lens placode to form the cornea and the lens.

19. (B) The zygote continues to divide from the cleavage stage until it becomes the morula, a solid ball of cell. This in turn forms the blastula, a hollow ball of cell. The blastula inits turn invaginates to become the gastrula.

20. (B) Remember the order of classification: Kingdom, phylum, class, order, family, genus, and species. Members of a class are more alike than members of a kingdom or a phylum, but less alike than members of order, families, genera, and species.

21. (C) Lipases are enzyme involved in dietary lipid digestion. Pancreatic lipase is an enzyme involved in the digestion of triglycerides in fat to release free fatty acids.

22. (B) The Key to speciation is the inability of two populations to interbreed. If two populations can interbreed and produce fertile offspring, then they are not separate species ((B) is right). The unwillinginess to cross the riverbred does not indicate a biological inability to interbreed, merely a geographical obstacle ((A) is wrong ). The color and height of the offspring is irrelevant ((C) and (E) are wrong) as is the fact that the horses are primary consumers ((D)is wrong).

23. (D) The first half of the scientific name is the genus of the organism; the second half is the species of that organism.

24. (C) The trait is recessive since Aa people are normal. In an Aa x aa cross, 50% of the offspring will be Aa and the other 50% will be aa ,and the phenotypes will have the same ratio.

25. (D) The electron transport chain directly produces the pH gradient by pumping protons out of the mitochondrial matrix. This proton gradient is used to make ATP.

26. (A) Fitness is defined as the ability of an organism to pass its traits and genes on to the next and future generations. This is determined, in part at least, by the number of young produced, as well as by the survival of the young. There is no reason to believe that any of the young are raised better or worse than the others, Choice (A) is best---this is the indicated, compared to (C) and (E). Lions are social animals and often care for the young of others, particularly of related individuals. Genes can be passed on by caring for the young of relatives in a process called kin selection. A cousin probably shares a relaticely small percentage of genes, making the kin selection contribution to fitness weak ((B) is wrong). Choice (D) is raising unrelated young that do not share her genes, meaning that this does not improve her own fitness ((D) is wrong).

27. (C) According to the heterotroph hypothesis the first forms of life lacked the ability to synthesize their own nutrients, requiring preformed molecules. Gradually, the molecules spontaneously formed by the environment began to prove inadequate to meet their energy needs, and autotrphs and developed inresponse.

28. (C) Angiosperms are flowering plants that produce seeds enclosed in an ovary, e.g., the maple tree. Gymnosperms, on the other hand, do not have enclosed seeds, one example is the conifer.

29. (C) Fungi are eukaryotes, are typically saprophytic organisms, and are divided into true fungi---- such as yeast, molds.

30. (D) In a BB x bb Cross, 100 percent of the offspring will be Bb. Genotypically, they will be heterozygous, and phenotypically, they will have brown eyes, since brown is dominant.

31. (B) A normal sperm will have a haploid (23)number of chromosomes. It could have either an X or Y chromosome.

32. (E) All of these organism are bilaterally symmetrical, which implies that they have two inentical mirror images. Radially symmetrical organisms, which are symmetrical from top to bottom but not from left to right, include hydra, starfish, and jellyfish. These organisms are often round.

33. (E) Small population are subject to inbreeding. Due to the limited selection of mates available, it is much more likely in a small population that a mate will be related and will share recessive harmful allele. These alleles can be homozygous and expressed at a much higher frequency than would have occurred in a larger population ((E) is correct). The rate of mutation is not affected by the population size, but by physical factors such as radiation and chemical exposure ((A) is wrong ). There is no reason why natural selection will not occur in a small population ((B) is wrong). Polyploidy is irrelevant ((C) is wrong). If the animals live in the desert, then they are adapted for this environment and it cannot be said that this is a special hazard for this animal ((D) is wrong).

34. (A) The bird and rhinoceros engage in a symbiotic relationship known as mutualism. The rhinoceros provides the bird with insects that live on its hide, while the bird keeps the rhinoceros parasite-free.

35. (D) Meiosis has two divisions that create four haploid cells from one diploid cell, while mitosis result in two diploid cells from one diploid cell. Both mitosis and mitosis replicate DNA during interphase (mitosis) and interphase I (meiosis).

36. ( B) Stomata are pores in leaves that allow gases in and out of the leaf. The stomata close at night, when there is no light energy tocatayze the light reaction, in order to prevent loss of water through transpiration in the stomata.

37. (B) when calcium binds troponin, it exposes a site that allows actin to bind to myosin, causing shortening of the sarcomere and muscle contraction.

38. (B) All organisms produce proteins through the triplet code. However, some of them do not need carbon dioxide or oxygen ( and, in fact, some, such as tetanus, are poisoned by oxygen). All organisms use ATP as cellular energy. Only eukaryotes, however, have membrane-bound oeganelles.

39. (E) This is a basic cross using Drosophila melanogaster. You’re told that the gene for wing type is located on an autosomal chromosome, a non-sex chromosome, which means that it is NOT inherited as a sex-linked trait, you’re also told that the dominates in nature. The recessive allele codes for the vestigial wing type, which is a stumpy wing. The gender of the flies is of no relevance here; gender only comes into play for sex-linked traits. So, our male fly is homozygous dominant and a homozygous recessive yields 100% heterozygous individuals, which have wild-type wings.

40. (B) In an ecological succession, each stage causes changes in the ecosystem that allow for the next stage to develop. If you start with a pond, it will ultimately become filled in with earth. Populations change until the climax community, a woodland, is reached. Frogs and snakes would be found in an intermediate stage of this ecological succession, when the pond is transformed into moist land.

41. (A) In the same ecosystem, there can never be two species in the same niche; if species are found together here, they MUST occupy different niches.

42. (C) The nitrogen-fixing bacteria form nodules on the roots of legumes so that elemental nitrogen (N₂) eventually can be converted to useable nitrogens, fertilizing the soil for other plants.

43. (C) Uracil is found in RNA instead of thymine. It bonds with adenine through two hydrogen bonds while,cytosine bonds with guanine through three hydrogen bonds.

44. (B) Asexual reproduction is more efficient than sexual reproduction in terms of the number of offspring produced per reproduction, the amount of energy invested in this process, and the amount of time involved in the development of the young, both before and after birth. Overall, sexual reproduction is a much more time-consuming, energy-consuming process than its asexual counterpart.

Asexual reproduction, however, must rely heavily on mutation to introduce phenotypic variability in future generations, since it almost exclusively produces genetic clones of the parent organism. Sexual reperoduction invoives the process of metosis. Recombination and independent assortment during meiosis allows new mixing of alleles that does not occur in asexual reproduction, as well as contribution of alleles from each parent during fertilization. Two genetically unique nuclei, the sperm nucleus and the egg nucleus, fuse to form an equally genetically unique zygote. Phenotypic variability is in this way introduced into individuals in a population, and can allow the population to adapt to a wider variety of conditions.

45. (E) DNA is the genetic material for all prokaryotes and eukaryotes.

46. (A) The glomerulus is is a network of capillaries in the Bowman’s capsule of the kidney.

47. (B) In the proximal convoluted tubule, almost all of the amino acids, glucose, and important salts are actively resorbed from the glomeruler filtrate back into the bloodstream.

48. (E) ADH acts to make the collectingduct more permeable to water, thereby increasing water reabsorption from urine to make it more concentrated.

49. (C) The nephron is involved in maintaining fluid balance in the body and is crucial for maintenance of homeostasis. It also acts to excrete nitrogenous wastes as part of the excretory system.

50. (A) As stated in the explanation to question 46 above the glomerulus is a network of capillaries in the bowman’s capsule of the kidney. Capillaries are part of the circulatory system.

51. (A) Digestion of starches begins in the mouth as salivary amylase breaks them down into maltose. This is why if you chew bread for long enough, it begins to taste sweet.

52. (B) The gall bladder stores bile produced by the liver. Bile emulsifies (or increases the surface area of ) fats. Hormones released in response to fat comsumption cause the gall bladder to release bile into the small intestine.

53. (D) The large intestine is responsible for most of the water and Vitamin K absorption that our body needs.

54. The pancreas both releases digestive enzymes and bicarbonate ions ( in what is termed exocrine function) and secrates glucagon and insulin to control blood glucose levels ( endocrine function). Exocrine secretions are released through a duct to act locally. Endocrine secretions enter the bloodstream and are carried to distant sites to act.

55. (B) Oxytocin is released by the posterior pituitary. It increases uterine contraction during child-birth.

56. (E) Glucagon is released by the pancreas. It causes the breakdown of glycogen into glucose, increasing the glucose concentration of the blood.

57. (D) Aldosterone increases sodium resorption in the nephron. Water and chloride ions follow passively and water resorption is increased.

58. (C) Progesterone is secreted by the corpus luteum. Its function is to thicken the uterine lining preparing it for implantation of the fertilized egg.

59. (D) Bacteria do not have a developed vascular system instead, they exchange fluids, nutrients, and wastes with the environment through diffusion and transport across the cell membrane.

60. (E) Humans have a four-chambered heart that oxygenates blood at the lungs. It transports fluid, nutrients, and wastes throughout the body via a system of vessels knownas arteries, capillaries, and veins.

61. (B) Segmented worms have a closed circulatory system, with dorsal and ventral vessels and five aortic arches (hearts) that force the blood through the body.

62. (B) The endoplasmic reticulum is a membranous network that is the site of synthesis of proteins that are secreted or are packaged for delivery to membranes.

63. (E) Lysosmes are membrane-bound sacs of digestive enzymes with very low pH. Degradation of proteins or other macromolecules can occur here.

64. (A) The nucleus contain the genome and is the site at which genes are used to make mRNA.

65. (C) The ribosome is either attached to the ER or floats freely in the cytoposed of proteins and rRNA.

66. (E) The nucleolus is a region of the nucleus where rRNA is synthesized.

67. (A) mRNA is coded directly from the DNA of the cell and directs protein translation.

68. (C) tRNA carries its specific amino acid to the ribosome, where it attaches to the growing polypeptide chain coded for by mRNA.

69. (A) Organisms in a population have differences in their phenotypes caused by their genes. These differences will cause some individuals to survive better and pass on their traits to more offspring. This is the essence of natural selection.

70. (B) Adaptive radiation may be defined as the development of a nuber of different species from a common ancestor as a result of differing environmental pressures.

71. (C) Vestigial structures appear uselees, but in fact had a necessary ancestral function. One example is the appendix of man, which helped early humans to store and digest food, but now has no apparent function.

72. (B) A nucleotide is madeup of a sugar, a phosphate group, and a nitrogenous base. This nucleotide is the building block of nucleic acids such as DNA and RNA.

73. (C) An amino acid contain an amino group, a carboxylic acids group, and one of 20 varying R groups. Amino acids serve as the building blocks of proteins.

74. (A) A trigyceride is a lipid that consists of three fatty acids ( carboxy1 groups) bound to one glycerol molecule.

75. (D) Carbohydrates are organic molecules with H:O ratio of 2:1. Examples include fructose, glucose, sucrose, maltose, galactose, and other sugars.

76. (A) An animal’s primary goal in cold weather is to keep warm. It wants to limit the amount of heat lost, the environment, because the more heat it loses, the colder the animal feels. The amount of heat transferred from a body to its external environment is directly proportional to the amount of surface area exposed surface area, then it follows that the greater the surface area that is exposed, the greater the amount of heat is that will be lost. Smaller animals have a tougher time than larger ones trying to maintain a constant internal body temperature, because smaller animals have a greater surface area-to-volume ratio and a higher metabolic rate than large ones. Therefore, smaller animals both generate more heat and lose more heat to the environment than ones. If a group of small animals can somehow decrease their collective surface area-to-volume ratio, then they will lose less heat as a unit. This is accomplished through huddling.

77. (C) Sweating dissipates heat produced by the animals. Sitting in the shade and burrowing mean while, cool the external environment rather than diispating heat.

78. (C) You’re being asked to draw a conclusion about what it mwans for all organs, including the brain, to have a single body temperature. If an animal must keep ALL of its vital organs at the same temperature, and if one particular organ, such as the brain, is particularly sensitive to temperature, then the animal is obligated to maintain its body temperature the temperature required by that organ.

79. (E) On the graph, the animal from the list with highest relative metabolic rate is the cactus mouse. Only one animal has a higher metabolic rate-----the shrew. The lowest metabolic rate included in this chart is the horse’s.

80. (B) Because strain 2 cannot produce threonine on its own, it cannot grow unless the medium is supplemented with threonine.

81. (D) Strain 3 does not grow when it is supplemented with arginine and threonine; therefore, it obviously does not need them from the environment to grow. It does, however, need histidine to grow, and cannot produce it on its own as evidenced by the fact that it will grow when histidine is supplemented.

82. (A) Mutation occur in the DNA and are passed on to the proteins that are translated via the mRNA.

83. (B) The mutation did not affect strain 4’s ability to synthesize amino acids. This strain grows well regardless of whether or not its medium is supplemented. It is likely that its mutation is a silent mutation.

84. (B) Graph 2 shows normal growth with an abrupt cutoff when the bacteriophage is introduced and begins to lyse bacteria.

85. (E) Graph 5 shows a lag from normal growth, during which perios the medium does not have enough nutrients, followed by an exponential surge in growth when nutrients are added.

86. (C) Graph 3 shows exponential growth ---until the bacteria use up most of their nutrients and reach a plateau. The growth is the same as growth in rich media, since adding more nutrients cannot make the bacteria grow nuch faster.

87. (A) The labelled oxygen from the carbon dioxide shows up in the plant-formed carbohydrates; therefore, this must be the source of the oxygen for carbohydrate synthesis.

88. (B) The labelled oxygen rrom the water is not incorporated into the starch, and therefore, must be released as molecular oxygen when is split.

89. (D) Like water , the plant would split the H₂ SO₄into 2H⁺ and SO₄^2-.

90. (D) Chlorophyll captures light energy and passes it to the photosystems that creat the NADPH and protein gradient used to make ATP and carbohydrates in the dark reactions.

91. (B) The light reaction occurs in the thylakoid membrane of the chloroplasts, while the dark reaction occurs in the stroma of the chloroplasts.

92. (A) The Calvin cycle is known as the dark reaction because it does not use light directly. Instead, it utilizes ATP and NADPH produced from the light reaction as energy.

93. (D) Primary consumers eat producers; in this population, insects eat shrube.

94. (E) The decomposers that break down dead and decaying material are not presented in this pyramid. An example of a decomposer would be a fungus that feeds on fallen trees.

95. (B) Because organisms at upper levels derive their food energy from lower levels of the food chain, and because energy is wasted from one level to the next, smallerbionasses can be supported as the food chain is ascended. Biomass is continuously lost through wastes and other metabolic processes.

12^TH DIAGNOSTIC TEST

Part A

Directions: Each of the questions or incomplete statements below is followed by five suggested answers or completions. Choose the one that is best in each case and then blacken the corresponding space on the answer sheet.

1. The hardy-weinberg principle applies to

(A) The cell theory

(B) The theory of spontaneous generation

(D) Population genetic

(E) The germ theory of disease

2. The technique of DNA fingerprinting has been used to identyify people in crimed, accidents, and family relationship. In order to analyze the DNA of members of the same family, it is necessary to examine samples of their tissue for

(A) Similarities in the nucleotide uracil

(B) Similarities in dexoxyribose sugar

(D) Similarities in nucleotide base pairs

(E) RNA differences

3. The scientist who first brought about the artificial production of mutation through the use of X rays was

(A) Mendel

(B) Mendeleff

(D) Morgan

(E) Muller

4. The cell of cocn plant contains a diploid number of 20 chromosomes. When it divides by mitosis, what is the number of chromosomes in each of the resulting cells?

(A) 10

(B) 15

(D) 30

(E) 40

5. The exchange of gases between a leaf and its environment takes place through special structures known as the

(A) Cambium

(B) Lenticels

(D) Stomates

(E) Xylem

6. The bionie in which an ecologist would expect to and the coldest year-round temperature is the

(A) Taiga

(B) Coniferous forest

(D) Tundra

(E) Grassland

7. Which of the following would be most likely to occur in an ecosystem?

(A) As the number of prey decreases, the number of predatore increases.

(B) As the number of predators increases, the number of prey increases.

(D) As the number of prey increases, the number of predatore decreases.

(E) As the number of predators decreases, the number of prey decreases.

8. The transpiration rate a tree would most probably be increased by

(A) Increase in temperature only

(B) Increase in both humidity and temperature

(D) Increase in both humidity and air movement

(E) Increase in both temperature and air movement

9. Astrnautsare not likely to find active heterotrophy aggregates in any future exploration of the moon because.

(A) The force of gravity on the moon is too weak

(B) The force of gravity on the moon is too strong

(D) There is no atmosphere or water on the moon

(E) It is now suspected that there are moonquakes on the surface

10. The scientific name of the dog is cains familiaris and that of the coyote is Canis latrans. This indicates that both the dog and the coyote are members of the

(A) Same genus but different spacies

(B) Same species but different genera

(D) Same species but different classes

(E) Same class but different genera

11. If a family has four children three boys and a gift, what are the chances that the next child will be a girl?

(A) 0

(B) 1 in 2

(D) 1 in 4

(E) 1 in 8

12. In which of the following organisms does aerobic respiration take place?

I. Mammals

II. Higher green plants

III. Protozoa

(A) I only

(B) II only

(D) II and III only

(E) I,II, and III

13. The structure of a lipid contains all of the following EXCEPT

(A) A carboxyl group

(B) A CH₂O basic structure

(D) A fatty acid molecule

(E) An OH group

14. All of the following are mammals EXCEPT the

(A) Propoise

(B) Shark

(D) Walrus seal

15. During replication, a portion of a DNA molecule will separate between adenine and

(A) Guanine

(B) Thymine

(D) Uracil

(E) Adenosine

16. RNA is found in

(A) The nucleus only

(B) The cytoplasm only

(D) Protein

(E) Amino acids

17. Which of the following statements about proteins is true?

(A) All proteins are enzymes

(B) Al l proteins have catalytic properties

(D) The 20-odd amino acids are synthesized from proteins.

(E) DNA and RNA are highly structured proteins.

18.

Phaces

In the pedigree of a family shown above brown eyes are indicated as O and blue eyes as O. Joan and Jane are twins. From this chart, it can be determined that:

(A) Thomas and Mary are homozygous for brown eyes

(B) Joan and Jane are indentical twins

(D) Jane is homozygous for blue eyes

(E) Joan and Samuel are homozygous for brown eyes

19. A plant breeder obtained 252 red, 235 white, and 503 pink flowers, when he crossed pink snap-dragons. From this information, which of the following conclusions can be drawn?

(A) The phenotype of the hybrid is the same as its genotype.

(B) The phenotype of the pure type is different from its genotype.

(D) The offspring show the phenotype of the dominant gene.

(E) All of the above statements are false.

20. The following series of processes occurs in living things:

energy

(A) C₄ H₁₂O₆+6O₂-------à6CO₂ +6H₂O+ energy

energy

(B) 6CO₂+12H₂O---------à C₄H₁₂O₄+6H₂O+6O₂

Chlorophyll +energy

Enzymes

Which of the following organisms is capable of performing the processes represented by both equation A and equation B?

(A) An ameba

(B) An earth worm

(D) A bean plant

(E) None of these organisms

21. The energy reuirements of differentpeople very. Which of the following persons would most likely have a calorie requirement of 4,7007

(A) A 15-years-old girl weighing 52 kilograms

(B) A clerk weighing 81 kilogrames

(D) A coal miner weighing 67 kilograms

(E) A housewife weighing 63 kilogrms

22. Analysis of a certain complex compound shows that its molecule contains a phosphate molecule, a ribose molecule and a pyrimidine nitrogen base. Which of the following is the most informative statement that can properly be made about the compound on the basis of this information?

(A) It is most likely ribonucleic acid.

(B) It is DNA

(D) It contains thymine

(E) It is a polypeptide.

23. A limitation of the electron microscope is that it

(A) Surface loss of resolving power above a magnification of 1000X

(B) Cannot be used to study living cells

(D) Uses short-wave electrons

(E) Requires the use of balsam oil, which is becoming scarce

24. Which statement concerning ribosomes is true?

(A) They function in cell division

(B) They contain DNA.

(D) They are the sites of protein synthesis.

(E) They to contrace

25. As the number of neutrons in the nucleus of an atom increases, the atomic number of the atom

(A) Increases

(B) Decreases

(D) Varies with the form of the isotope

(E) Depends on the number of electron

26. Because urea is a nitrogen compound, it cannot be derived from the metabolism of

(A) Peptides

(B) Polypeptides

(D) Proteins

(E) Amino acids

27. The relationship described in a food chain may also be expressed as a food pyramid. The major difference is that in the food pyramid, as depicted in the accompanying diagram, there is an indication of both relative numbers of individuals and the amounts of energy involved at each level.

Phaces

Which of the following best summarize this relationship?

(A) When the top of the pyramid is reached, the number of individuals decreases but the amount of energy increases.

(B) When the top of the pyramid is reached, the number of individuals increases, and the amount of energy remains the same as at the other levels.

(D) At the bottom levels of the pyramid, both the number of individuals and the amount of energy involved are lowest.

(E) At all the levels, the number of individuals and the amount of energy are the same.

28. In which of the following organisms does transpiration take place?

I. Car

II. Maple tree

III. Paramecium

(A) I only

(B) II only

(D) II and III only

(E) I,II, and III

29. During the process of respiration, energy is transferred from glucose molecules of

(A) ACTH

(B) DNA

(D) ATP

(E) BCG

30. In the nitrogen cycle, nitrogen compounds are broken down by decomposers to release

(A) Ammonia

(B) Carbon dioxide

(D) Vinegar

(E) Urea

31. Rh blood disease can occur when a Rh-negative mother

(A) Develops erythroblastosis

(B) Fails to form antibodies

(D) Has an Rh-negative baby

(E) Has an Rh-positive baby

32. Which of the following is illustrated by an organism that exists in a helpful relationship with other organism?

(A) Photosynthesis

(B) Autotropism

(D) Parasitism

(E) Mutualism

33. The tube that brings urine from the kidneys to the bladder is the

(A) Urethra

(B) Ureter

(D) Eustachian tube

(E) Bile duct

34. A nerve cell that receives stimuli from the outside is know as a(n)

(A) Motor neuron

(B) Sensory neuron

(D) Intemeuron

(E) Ganglion

35. A vacant lot may have organisms such as timothy grass, dandelions, ants, soil bacteria, earthworms, ailanthus trees, and mice living in it. Together, all of these organisms comprise a

(A) Population

(B) Biome

(D) Community

(E) Climaz

36. Which of the following does a period of 4 billion years represent?

(A) The estimated age of the earth

(B) The duration of the age of dinosaurs

(D) The speed of light in years

(E) The time that has lapsed since primitive humans first appeared

37. According to the system of classification, which of the following is LEAST closely related to the other(s)?

I. Horse

II. Human

III. Sea horse

(A) I only

(B) II only

(D) II and III only

(E) I,II, and III

38. Most ceila lacking a cell will also lack

(A) Mitochondria

(B) Chloroplasts

(D) A vacuole

(E) A Golgi complex

39. Plankton is the name given to the algae protozoan and other forms of microscopic life that a bound on the surface of the ocean. Which of the following best describes the most important role of the plankton in nature?

(A) It serves as the basis of the food chain for marine life.

(B) It is useful as human food.

(D) It serves directly as the basic diet of most fish.

(E) It is the basis of autotrophic nutrition

40. In an area populated by all of the following animals which would probably have the largest population

(A) Foxes

(B) Field mice

(D) Skunks

(E) Moles

41. When solar energy reaches a green plant cell, which of the following occurs?

(A) The solar energy is obsorbed

(B) All of the wavelengths of the solar energy are reflected by the green chlorophyll.

(D) An electron drops from its normal energy value to a lower level.

(E) An electron becomes ”excited” and is destroyed

42. Which of the following statements about Linnaeus’s system of classification is FALSE?

(A) Every organism has a genus and a species name.

(B) Organisms are classified mainly according to habitat.

(D) A species consists of closely related organisms that are similar in structure and can interbreed.

(E) A genus consists of one or more species that show many similar ions.

43. Which of these statements is LEAST bits when they were first introduced into Australia?

(A) They multiplied rapidly

(B) ..

(D) They found the climate beneficial to survival.

(E) They were affected by few natural enemies

44. The thyroid gland

(A) Is known as the gland of emergency

(B) Stimulate the liver to store glycogen

(D) Regulates the rate of metabolism

(E) Contains the islands of langerhans

45. A study was made of the daily activities of the average farmer’s wife, weighing 62 kilograms, in New York State. The following table shows a day’s activities, the time spent on each, and the output of energy in calories per kilogram per hour.

Activity

Hours

Output of Energy (cal/kg/h)

Sleeping

Sitting quietly

Eating

Laundering

Sweeping

Dishwashing

Driving car

Going upstairs

Going downstairs

Walking

1¹/₂

1.0

0.4

1.3

1.4

1.0

0.9

14.7

4.1

2.0

Which of the following represents the total energy requirements of the farmer’s wife, in calories, for such a day?

(A) 2,000--2,200

(B) 2,200—2,400

(D) 2,600—2,800

(E) 2,800—3,000

46. In 1889 a biologist named August Aeissmann atterapted to see if he could produce a strain of mice without tails. He surgicaily removed the tails of mice and permitted them to reproduce. The result was that all of the offspring had long tails. He repreated the procedure for 22 generations of mice but always observed the same result. He research helped disprove the theory of

(A) Natural selection

(B) Survival of the fittest

(D) Inheritance of acquired characteristics

(E) Continuity of germplasm

47. A color –blind man marries a normal woman who is heterozygous for color vision.what are the chances of their two being color –blind

(A) 0%

(B) 25%

(D) 75%

(E) 100%

48. The number of different gene combinations possible in the gametes of a trithybird pea plant.TtYySs,is

(A) 2

(B) 4

(D) 8

(E) 10

49. A bacillus divides every half hour,under ideal conditions of food and temperature. After 4 hours.what will be the bacilli?

(A) 4

(B) 8

(D) 128

(E) 256

Questipns 50-54 refer to the following diagram of a cell.

50. Which of the following functions as site of protein synthesis?

(A) 8

(B) 5

(D) 7

(E) 2

51. All of the following are organelles EXCEPT

(A) 7

(B) 5

(D) 2

(E) 3

52. Which of the following is believed to function in intracellular transport?

(A) 3

(B) 7

(D) 4

(E) 5

53. Cellular respiration occurs at

(A) 7

(B) 9

(D) 5

(E) 4

54. Of the following.which contains molecules of DNA?

(A) 5

(B) 3

(D) 4

(E) 8

PART B

‘Direction: Each set of lettered choices below refers to the numbered statements immediately following it. Choose the one lettered choice that best fits each statement and blacken the corresponding space on the answer sheet. A choice may be used once,more than once,or not at all in each set.

Questions 55-58

(A) Crop rotation

(B) Contour

(D) Erosion

(E) Insect control

55. A farmer plows in concentric circles around a hill

56. A windstorm carries so much dust that visibility is reduced almost to zero

57. A farmer plant clover on a field that had been used for corn

58. Some vanishing wildlife is beginning to reappear in previously heavily timbered areas.

Question 59-63

(A) Meiosis

(B) Mitosis

(D) Mutation

(E) Crossing-over

59.Process by which the number of chromosomes is reduced

60.Process by which the chromosome number is restored

61.Process by which the chromosome number is kept constant in all the cell of an organism

62.Process by which chromosomes exchange materials

63.Process by which genes change in composition

Question 64-68

(A) Tropism

(B) Simple reflex

(D) Conditioned response

(E) Habit

64. A secretary takes dictation in shorthand

65. A plant that was blown over on its side begins to grow upward

66. A robin builds a nest.

67. A boy blinks as a basketball is thrown at his face

68. A dog’s mouth waters when his master picks up his feeding dish

Question 69-73

(A) Petrification

(B) Sedimentation

(D) Radiation from carbon-14

(E) Refrigeration

69. How the struta of rock in the Grand Canyon were

70. How the bone of a dinosaur was preserved

71. How the horse changed through the ages

72. How the wood of a tree turned to stone

73. How the age of the remains of primitive humans is determined

PART C

Direction: Each group of question below concerns tastory or experimental situation. In each case, first the description of the situation. Then slect the best answer to each question following it and on the corresponding space on the answer sheet

Question 74—73

The best tubes shown in the diagram below were set determine the conditions under which an enzyme the human digestive system. Each test tube was with four small cubes of hard-boiled egg white, tube measuring 3 millimeters in size. After the test had been filled with the liquid indicated in the ,they were then kept for 24 hours in an or at 37°C. At the end of that time, it was observed the egg white in test tube 3 had disappeared.

Phaces

74. The part of the human digestive system in which this type of action would take place is the

(A) striat intestine

(B) stomach

(D) large intestine

(E) pancreas

75. The control in this investigation was test tube

(A) 1

(B) 2

(D) 4

(E) 5

76. The most reasonable conclusion that can be drawn from the result observed is that

(A) egg white is digested by a combination of an acid and a base

(B) all enzymes require an acid solution to carry on catalysis

(D) the more acid the solution, the more effective is the action of pepsin

(E) egg white consists of protein and therefore requires an acid for deamination to take place

77. The incubator was set at 37°C because

(A) enzymes are kept sterilized at that temperatur

(B) bord-boiled egg white remains solid at that temperature

(D) that is the best temperature for an acid and a base to neutralize each other

(E) that is the temperature at which pepsin is least with

78. The acid nest probably used in this investigation was

(A) hydrochloric acid

(B) amino acid

(D) ---COOH

(E) nucleic acid

Question 79--84

A technique has been perfected by which the tip of a root can be cut and placed in a sterile nutrient solution. Here, under controlled conditions of temperature, it will grow in length and produce secondary root. A research scientist made daily measurements of a tomato root tip growing at 33°--35°C this way. The accompanying graph shows the results.

Phaces

79. The time when the length of the root was increasing at the greatest rate was

(A) during the 1^st day

(B) between the 1^st and 2^nd days

(D) between the 3^rd and 4^th days

(E) between the 6^th and 7^th days

80. The root tip showed no growth

(A) at the end of the 1^st day

(B) at the end of the 3^rd day

(D) at the end of the 10^th day

(E) at no time shown on the graph

81. The root tip had achieved more than half of the total length indicated on the graph within the first

(A) 3 days

(B) 4 days

(D) 6 days

(E) 7 days

82. The smallest increment in growth was achieved

(A) during the first 3 day

(B) during the last 3 day

(D) on the 3^rd day

(E) on the 8^th day

83. The S-shaped appearance of the growth curve indicates that

(A) the rate of growth was greatest after a few days, and then it decreased

(B) the root tip increased in length at a uniform rute

(D) the root tip grew more slowly than the region of elongation

(E) mitotic division of the root tip cells occurred at intervals

84. the graph would have appeared as a straight line if

(A) the growth after the 8^th day had been at the same rate as on the preceding day

(B) the root tip had increased in length at the same rate daily

(D) the growth increment of the first 2 day had been identical

(E) the nutrient solution had been re-enforced with root growth hormone

Question 85-87

The rang of random variation in the size of 1,000 lima beans in shown as a bell-shaped curve in this graph

Pheces

85. If a plant breeder selected only the longest seeds for planting each year for 10 years, the range of variation in the size of 1,000 lima beans would most likely be as shown in which of the following graphs?

Pheces

86. If the plant breeder selected only the shortest seeds over a 10—year period, which of the graphs shown as answer choices for question 85 would be most likely to represent the range of variation in the size of 1,000 lima beans?

(A) A

(B) B

(D) D

(E) E

87. Which of the following might most seriously interfere with the predictable results in regard to lima bean size?

(A) A passing tornado destroyed the bean crop

(B) An illness of the plant breeder one summer prevented him from adding fertilizer to his crop

(D) A mutation caused a change in the size of the pistils.

(E) The breeder had to spray an insecticide to protect the bean plants from beetles.

Question 88-91

In comparing the effectiveness of enzymes at various pH concentrations, the accompanying graph was prepared to show the maximum rate of activity for maltase.

Phaces

It was also determined that pepsin is most active at pH 1.5-2.2, and trypsin at pH 7.9-9.0.

88. The graph shows that

(A) point X represents pepsin and point Y represents typsin

(B) point X represents maltase and point Y represents pepsin

(D) point X represents pepsin and point Z represents maltase

(E) point X represents pepsin and point Y represents maltase

89. The pH concentrations at which maltase is least effective are

(A) 1 and 7

(B) 1.5 and 7.9

(D) 2.2 and 9.0

(E) 1 and 14

90. On the basis of the graph, the temperature at which maltase is most active

(A) is the same as the temperature at which pepsin is most active

(B) is different from the temperature at which pepsin is most active

(D) is different from the temperature at which trypsin is most active

(E) cannot be determined

91. The nutrient substrate acted on by maltase is most likely

(A) glycerol

(B) carbohydrate

(D) amino acid

(E) lipid

Question 92-93

In an experiment, a few drops each of concentrated MnSO₄ ( manganese sulfate ) and NaOH ( sodium hydroxide) added to a solution containing O₂ ( oxygen ) will cause a brown precipitate. The greater the O₂contain, the deeper the brown color of the precipitate, were filled with water. A sprig of Elodea was placed in tubes, marked A, B and C were placed in the sunlight. Tube B was placed in the dark. After three hours the Elodea was removed and three drops of each testing substance were added to all three tubes. The precipitate of darkest color was found in tube A.

92. Which of the following is most clearly illustrated by this experiment?

(A) Only green plants carry on photosynthesis.

(B) Green plants carry on respiration.

(D) Sunlight alters the O₂ content of the water.

(E) Green plants use up O₂ in the dark.

93. For an additional control, the experimentes should have

(A) used another type of water plant

(B) used another test for oxygen

(D) set up a tube in the dark with no plant

(E) added oxygen to the three drops of the testing substance

Question 94—95

A flock of prize poultry became infected with a strange disease of unknown cause. After half of the flock had died, scientist were called in to try to determine the exact cause of the disease.

94.Which group of materials would be most useful in this research?

(A) Sterilizer, microscope, penicillin, filter paper, petri dishes

(B) Thistle tubes, agar nutrient,oenicillin, filter paper, micrometer

(D) Petri dishes, filter paper, microscope, tripod magnifier, sterilizer

(E) Lncubator, penicillin discs, agar nutrient, filter paper, micrometer

95. At which point is it reasonable to believe that the research problem is being solved?

(A) When the suspected germ has been recovered from the tissues of birds made experimentally ill by inoculation

(B) When all the infected birds begin to recover from the disease, instead of dying

(D) When there is evidence that the remaining healthy birds have developed a natural immunity to the disease

(E) When there is no further incidence of the disease among the members of the flock

Answer Key: Diagnostic test

1 (D) 31 (E)

2 (D) 32 (E)

3 (E) 33 (B)

4 (C) 34 (B)

5 (D) 35 (D)

6 (D) 36 (A)

7 (C) 37 (D)

8 (E) 38 (B)

9 (D) 39 (A)

10 (A) 40 (C)

11 (B) 41 (A)

12 (E) 42 (B)

13 (B) 43 (B)

14 (B) 44 (D)

15 (B) 45 (D)

16 (C) 46 (D)

17 (C) 47 (C)

18 (D) 48 (D)

19 (A) 49 (E)

20 (D) 50 (C)

21 (D) 51 (D)

22 (A) 52 (D)

23 (B) 53 (A)

24 (D) 54 (E)

25 (C) 55 (B)

26 (C) 56 (D)

27 (C) 57 (A)

28 (B) 58 (C)

29 (D) 59 (A)

30 (A) 60 (C)

61 (B) 91 (B)

62 (E) 92 (C)

63 (D) 93 (D)

64 (E) 94 (C)

65 (A) 95 (A)

66 (C)

67 (B)

68 (D)

69 (B)

70 (A)

71 (C)

72 (A)

73 (D)

74 (B)

75 (E)

76 (C)

77 (C)

78 (A)

79 (D)

80 (E)

81 (B)

82 (B)

83 (A)

84 (B)

85 (D)

86 (C)

87 (D)

88 (E)

89 (E)

90 (E)

Answers Explained: Diagnostic Test

1. (D) The Hardy-Wsinberg principle states thet the gene pool of a population remains constant from generation to generation if the population is large, there are random mating, and no new factors are introduced, such as mutations or migration.

2. (D) DNA segments of different people have different sets of nucleation. People who are related would have many similar sets of nucleotides. When samples of blood, semen, hair cells, or other tissues containing nuclei are analyzed, the DNA sequences can be analyzed by a special procedure which includes a technique called gel electrophoresis.

3. (E) Herman J. Muller produced mutations artificially in Drosophila flies in 1927.

4. (C) During mitosis, each of the 20 chromosomes of the cell splits lengthwise into two identical chromosomes. These separate from each other and move to the opposite sides of the cell, while the cell itself divides into two cells, each now containing the same number, 20, as the original cell.

5. (D) Stomates are the tiny openings inthe leaf epidermis

6. (D) The tundra is the treeless region in the far north. It has an ardic climate of sever cold, with a long, dark winter, and a mild summer having continuous daylight.

7. (C) The number of predators depends on their ability to catch prey. If more prey are available, the predators will be more successful and their numbers will increase

8. (E) With an increase in temperature there is an increase in the actives of the plant, including transpiration. Air movement removes

9. (D)

10. (A)

11. (B) Each time an egg is fertilized, it unites with a sperm, which may contain either the X or the Y chromosome. Thus, there is one chance out of two that a sperm with an X chromosome will unite with the egg, resulting in a girl .

12. (E) Aerobic respiration takes place in the presence of oxygen. It releases the chemical bond energy of food into energy that can be used by all three types of organisms listed.

13. (B) Like carbohydrates, lipids contain carbon hydrogen, and oxygen. However,

they differ in that the hydrogen and oxygen in carbohydrates are present in the same ratio as in water 2:1.CH₂O is therefore a basic structure of carbohydrates, not lipids.

14. (B) The shark is a member of the class Pisces and thus is a fish. All the others are members of the class Mammalia---they are warm-blooded and give birth to their young alive.

15. (B) The bases of the DNA model are always arranged in pairs. Adenine is paired with thymine ;cytosine, with guanine.

16. (C) RNA is formed in the nucleus from the pattern, or template, of DNA. It then passes into the cytoplasm.

17. (C) Enzymes are organic catalysis that can speed up the rate of a biochemical reaction without being changed.

18. (D) Blue eyes are a recessive trait; that is two genes are needed for the trait to appear. Thomas and Mary are heterozygous for brown eyes, as is seen from the appearance of blue-eyed Jane. Joan and Jane are fraternal twins, since they do not have the same eye color. Joan and Samuel could be heterozygous for brown eyes, since their parents also produced a blue-eyed child.

19. (A) In incomplete dominance, the hybrid shows a blending of the colors of both parents, and therefore is seen to have one gene from each. The phenotype is the pink color of the hybrid. The genotype is the genetic makeup of the pink hybrid. This generation shows a 1:2:1 ratio

20. (D) Equation (A) represents the reaction involved in aerobic respiration. Equation (B) represents the reactions involved in photosynthesis. A bean plant caries on respiration all the time and photosynthesis in the light .

21. (D) A coal miner, being most active physically requires the greatest number of calories to carry on his heavy labor.

22. (A) Ribonucleic acid, or RNA, is composed of nucleotides that contain a phosphate, ribose, which is a five-carbon sugar, and a nitrogen base, either a purine ( adenine or guanine ) or a pyrimidine ( cytosine or uracil). DNA has a deoxyribose sugar and a pyrimidine base that os thymine rather than uracil.

23. (B) The electron microscope uses a stream of electrons and produces an image of the object on a screen or a photographic plate. The specimen is placed in a vacuum chamber because any air in the tube would interfere with the motion of electrons. Living cells not exist in the vacuum.

24. (D) Ribosomes are tiny granules found in the endoplasmic reticulum of the cytoplasm. They contain most of the RNA of the cell, and are the size of protein synthesis, including enzyme formation.

25. (C) The atomic number is determined by the number of protons in the nucleus. An increase in the number of neutrons creates a new isotope but does not change the atomic number of the element.

26. (C) Urea is a nitrogenous waste resulting from the breakdown, or deaminization of amino acids in the liver. Polysaccharides are large carbohydrate molecules consisting of many repeating glucose molecules bonded together; the only elements they contain are carbon, hydrogen and oxygen.

27. (C)Green plants are the basis of the food chain. They are also the base of the food pyramid, where they occur in the largest number. Green plants seve as the source of energy for the other organisms involved. There is a decrease in the amount of energy as it is passed along from the producers to the consumers.

28. (B) Transpiration refers to the evaporation of water vapour from the leaves of a plant such as the maple tree.

29. (D) During cellular respiration, energy is released from glucose by a series of complex steps. When glucose is broken down. Some of its hydrogen is removed, releasing energy that is transferred to ADP with the addition of a high-energy phosphate molecules to convert the ADP to ATP

30. (A) In one part of the nitrogen cycle, bacteria of decay in the soil decompose animal and plant remains that contain nitrogen aompounds into ammonia.

31. (E) When an Rh-postive fetus develops in an Rh –negative mother, its red blood cells may be destroyed by antibodies from the mother.

32. (E) Symbiotic organisms live together in an intimate relationship. For example, a tichen is composed of an alfa and a fungus. The alga makes food by photosynthesis, while the funus supplies water and minerals. This type of symbiosis in which both organisms benefit is called mutation.

33. (B) Each kidney is connected with the bladder by a ureter.

34. (B) A sensory of afferent neuron connects a sense organ with the brain or the spioal cord.

35. (D) The population of all the plants, animals, and other organisms living together in a given environment comprise a community.

36. (A) most scientists now believe that the earth is at least 4 billion years old.

37. (D) The sea horse is a species of fish. The other two choices are mammals and are more closely related to each other.

38. (B) Plants have cells with cell walls made of cellulose. Green plants would also contain chloroplasts.

39. (A) Plankton is the basis of all life in the ocean. The microscopic algae and protozoa serve as food for the slightly larger forms of life, which in turn are eaten by second other animals, including small fish. These are then preyed upon by larger fish.

40. (C) The grasshopper is the most numerous consumer listed. It is then eaten by secondary consumers, which are present in smaller numbers.

41. (A) In the green plant cell, solar energy of a particular range of wavelengths is absorbed by the green pigment chlorophyll.

42. (B) Linnaeus classified living things according to their physical characteristics. Organisms of the same habitat do not necessarily have similar characteristic (e.g. butterfly, bird, cow).

43. (B) One of the reasons rabbits were so successful in Australia is that there were only pouched mammals there, which did not serve as natural enemies to them .

44. (D) The thyroid gland secretes thyroxin, which is carried to the cells of the body, where it controls to rate at which oxidation takes place and energy is released.

45. (D) The output of energy for each activity is computed as follows

Activity

Houres

Output per Kilogram

Output for 62 Kg

1¹/₂

1.0 calories x62

0.4 calories x62

1.3 calories x62

Total

496.0 calories

49.6 calories

37.2 calories

120.9 calories

2,718.7 calories

46. (D) According to Lamarck’s explanation of evolution, if an animal uses an organ to adjust to its environment, that organ will become well developed; if it is not used, the organ will remain small and undeveloped. He believed that such acquired characteristics are inherited and passed on to future generations. Weissmann’s experiment showed that this is not so; the mice were still born with normal tails.

47. (C)The possible results are arrived at in this way:

Male: 50%normal;

50% color-blind

Female: 50% normal

carrier

50% color-blind

48. When the gametes are being formed, the alleles separate out during reducation-division to form the following possible types of gene combination: TYS,TYs, TyS, Tys, tYS, tYs, tyS, tys.

49. (E) In 4 hours , the bacilli will have divided 8 times. After the first division there will be 2;256 are formed

50. (C) Ribosome

51. (D) Pinocytic vesicle

52. (D) Endoplasmic reticulum

53. (A) Mitochondrion

54. (E) Chromosome

55. (B) Contour plowing prevents rainwater from running downhill rapidly and producing gullies.

56. (D) When soil is not held together by roots of plants, wind carries it away and acts as an agent of erosion.

57. (A) The roots of clover plants have swellings called noduies in which nitrogen-fixing bacteria are located; they form nitrates, thereby enriching, through crop rotation, soil depleted by a crop such as corn.

58. (C) Reforestation helps conserve forests, which act as homes for wildlife.

59. (A) During meiosis, rametes are formed with the monoploid number of chromosomes.

60. (C) When sperm and egg cells unite, the monoploid number of each contributes to the diploid number of the fertilized egg.

61. (B) During mitotic division, the resulting cells receive the same number of chromosomes as the original cell.

62. (E) When crossing-over occurs, part of chromosomes become attached to other chromosomes.

63. (D) The genes, which make up chromosomes, are changed during a mutation.

64. (E) Taking dictation is an example of a learned automatic activity that was acquired by having a desire to learn shorthand accompanied by a feeling of satisfaction, and after much practice.

65. (A) Turning responses of plants are known as tropisms. In this case, the plant shows negative geotropism and grows upward, away from the force of gravity. It many also be stimulated to grow toward light, showing positive phototropism.

66. (C) Nest building is an example of an instinct, which is an inborn, unlearned series of reflexes.

67. (B) Blinking is an example of an inborn, unlearned, and automatic response.

68. (D) There is an association between the original reflex of saliva production in the presence of food, and the feeding dish which contain food. This is a learned response.

69. (B) The strata originated in the layers of sediment that were deposited by rivers. Under the pressure of the water over a long period of time, these layers, or strata, become solidified into rock.

70. (A) Under the pressure of water, the particles of bone were gradually replaced by mineral matter, finally resulting in petrified bone.

71. (C) By a series of mutations, the earliest type of hours ( Eohippus ) changed from a small animal with four toes on its forelegs to the present animal, standing on a foot composed of one loc, having two small side splints which are the remains of toes.

72. (A) Under water, the organic structure of the tree was granually replaced by the fine mineral matter that covered it, turning it into petrified wood.

73. (D) The age is determined by computing the rate of decay of the carbon-14 present in these remains. It is known that the half-life of carbon-14 is 5,760 years.

74. (B) The stomach produces gastric juice, which contains hydrochloric acid, water, and the enzyme pepsin. Pepsin partially digests proteins in the food that reaches the stomach. It is active only in an acid medium.

75. (E) The control is that part of an experimental procedure that is not exposed to different treatments and that serves as a basis for comparion of the results.

76. (C) The enzyme pepsin digested the protein of the egg white so completely that it disappeared. Pepsin is active only in the presence of hydrochloric acid.

77. (C) Pepsin functions best at the temperature of the body, 37°C.

78. (A) Hydrechloric acid is naturally present in gastric juice and therefore would be the logical choice. Pepsin is active only in an acid medium.

79. (D) The curve on the graph shows the steepest rise from the 3^rd to the 4^th day.

80. (E) Growth occurred at all times.

81. (B) Within 4 days, the length of the root tip was 50 mm, of a total length of 99 mm.

82. (B) The curve begen to level off during the last 3 days, indicating a slower rate of growth.

83. (A) After a siow start, growth was rapid, then siow again.

84. (B) at a constant rate, there would have been a constant increase in length, leading to a straight-line graph.

85. (D) By selecting only the largest beans each year, the beans containing genes for smallness are gradually eliminated and the curve moves away from X and Y. The number of large beans keeps increasing until they are most numerous, with relatively little variation.

86. (C) When the smallest beans are selected for planting each year the genes for long seeds are gradually eliminated and the curve moves toward X. The number of small beans keeps increasing until they are most numerous, with relatiyely little variation.

87. (D) A mutation leads to an inherited change in the size of the pistils. This affects the size of the ovules they contain and, consequently, influences the size of the seeds that develop from them. All the other factors mentioned are environmental, and do not affect the inheritance of the genes.

88. (E) The maximum activity of pepsin (X) is shown on the graph at pH 1.5-2.2. the maximum activity of maltase (Y) is shown to take place at a pH of about 7.

89. (E) At pH concentrations of 1 and 14, the graph shows a decline in maltase activity to the zero level.

90. (E) The graph does not show a record of temperature activity.

91. (B) The enzyme maltase acts on maltase, which is a carbohydrate.

92. (C) The dark brown color in tube A indicates that more O₂ was formed in that tube. We may assume that photosynthesis carried on by the elodea sprig was responsible for the O₂. The re was little color in tube C because there was no Elodea sprig to produce O₂. The Elodea in tube B could not photosynthesize because of lack of light.

93. (D) The experimenter could see that there was less O₂ in the tube with Elodea placed in the dark (tube B ) than in the tube with Elodea placed in the light ( tube A ). He could not, however compare the O₂ content in a tube with Elodea that was placed in the dark, with the O₂ content of a tube without Elodea also in the dar.

13^TH DIAGNOSTIC TEST

Part A ( Questions 1-60)

Direction: Each of the questions or incomplete statements below is foolowed by five suggested answers or completions. Choose the one that is best in each case and then blacken the corresponding spaces on the answer sheet.

1. Lower forms of life such as protozoa, sponges, and jellyfish have continued to exist since earliest geologic times. Which of the following statements would Darwin have considered to be the best explanation for the continued existence of lower life forms to modern times?

(A) These organisms are still in the process of becoming extinct

(B) There is a fairly direct connection in evolution between the number of new forms that appea and the number of old ones that disappear.

(D) Some simpler organisms have a broad adapotion to the conditions of life.

(E) Simpler organisms continue to exist because they are able to inherit acquired characterist

2. In what part of the cell are proteins synthesied?

(A) Ribosome

(B) Nucleus

(D) Mitochondrion

(E) Golgi complex

3. The process of fertilization in both monocotyle-dons and mammals

(A) Requires an external watery environment

(B) Normally results in an embryo that requires yolk for food

(D) Restores the monoploid number of chromosomes

(E) Occurs within female reproductive organs

4. Whch of the following producres may be applied to help determine whether a child will be born having Down syndrome?

(A) Electron microscope examination of sperm and egg cells

(B) Weekly analysis of the mother’s urine sample

(D) Cloning

(E) X-ray diffraction of deoxyribose molecules

5. Which of the following represents the sequence of bases on the messenger RNA formed from a DNA sequence of CGG-ACT?

(A) CGG—TGA

(B) UGG—TGA

(D) CGC—ACT

(E) GGG—TGA

6. A synapse is

(A) Part of an axon

(B) Part of a neuron

(D) A chemical impulse

(E) An electrical impulse

7. The adrenal gland is located next to the

(A) Liver

(B) Brain

(D) Kidney

(E) Neck

8. The Mesozoic Era is called the age of Reptiles because at that time

(A) Reptiles first appeared

(B) Reptiles reached their greatest development

(D) Reptiles successfully resisted humans

(E) The dinosaurs became extinct

9. Darwin found that the finches on the various Galapagos Islands were somewhat different from each other because of

(A) Different food

(B) Geographic isolation

(D) Different climated

(E) The inheritance of acquired characteristics

10. In diabetes, excess sugar is found in the urine because

(A) The basal metabolism is decreased

(B) The kidneys are in a state of hypertension

(D) An excess of insulin is produced

(E) Insufficient thyroxin is formed

11. A paramecium is able to avoid obstacles in its path because its

(A) Sense organs receive responses

(B) Contractile vacuoles burst

(D) Protoplasm has the property of irritability

(E) Conditioned responses are inborn

12. Why can’t a grasshopper be drowned by keeping its head under water?

(A) It breathes through openings in its abdomen.

(B) The spiracles in its head filter out oxygen.

(D) It is cold-blooded

(E) The maxillae and mandibles serve as an airtight valve.

13. Chestnut trees are becoming extinct in the eastern part of the United State because

(A) The chestnut crop has been overpicked

(B) The Japanese beetle eats the leaves and roots

(D) The trees are susceptible to the white pine blister rust

(E) A fungus disease, the blight, is killing the trees

14. What is the reason that a blood clot in the coronary artery may be fatal?

(A) It leads to atherosclerosis

(B) Varicose veins invariably result as a by-product.

(D) The flow of blood to the heart muscle is blocked.

(E) The clot leads to coagulation of lymph.

15. The fact that, under certain conditions, stomatal openings become smaller plants to avoid excessive loss of

(A) Carbon dioxide

(B) Oxygen

(D) Essential plant hormones

(E) Chlorophyll

16. Down syndrome is a human defect caused by the presence of an extra chromosome; the affected individual has 47 chromosomes in the body cells instead of 46: Which of the following is the cause of this condition?

(A) Linkage

(B) Nonlinkage

(D) Sex linkage

(E) Chromosomal replication

17. To the species involved a major advantage of sexual reproduction over asexual reproduction is that sexual reproduction results in

(A) Greater number of offspring

(B) Greater variety of offspring

(D) More rapid development of offspring

(E) Less vulnerability of offspring

18. The phase-contrast microscope has aided our understanding of the cell by permitting

(A) Detailed observations of unstained living cells

(B) Magnification of cells up to 100,000 times their normal size

(D) Chemical analysis of part of the cell

(E) Ultraviolet-light penetration of cells

19. A man who is normal for blood clotting ability marries a normal heterozygous woman who came from a family having a history of haemophilia. The chance of their daughters being normal heterozygous is

(A) 25%

(B) 0%

20. There are 25 yellow and 25 green peas in each of two jars. A student simultaneously removes one bean from each jar at random and keeps a tally of the color of the pairs of beans obtained. According to the law of probability, what will the final result most likely be?

(A) 50 yellow-yellow; 50 green-green

(B) 25 yellow-yellow; 50 yellow-green;25 green-green

(D) 75 yellow-yellow; 25 green-green

(E) 50 yellow-green

21. Lactic acid, alcohol, and 2 ATPs are produced as a result of which of the following processes?

I. Aerobic respiration

II. Anaerobic respiration

III. Photosynthesis

(A) I only

(B) II only

(D) II and III only

(E) I,II, and III

22. All of the following are parasitic warns EXCEPT the

(A) Leech

(B) Liver fluke

(D) Tapeworm

(E) Ringworm

23. Which of the following kingdoms includes single celled organisms?

I. Monera

II. Protista

III. Fungi

(A) I only

(B) II only

(D) II and III only

(E) I, II, and III

24. A measurement of 0.6 millimeter is equal to

(A) 6 micrometers

(B) 60 micrometers

25. The process of protein involves which of the following cellular organelles?

I. Mitochondrion

II. Ribosome

III. Nucleus

(A) I only

(B) II only

(D) I and III

(E) II and III

26. A drop of anti-A blood-typing serum was placed on the left side of a slide, and a drop of anti-B serum on the right side. Then a drop of blood was mixed into the serum on the left, and another drop into the serum on the right. If the blood was type A, the red bold cells would be clumped on

(A) The right side only

(B) The left side only

(D) Neither side

(E) The type AB side

27. Enzyme synthesis in a living cell is most likely to ocuure in the

(A) Centriole

(B) Centrosome

(D) Ribosome

(E) Food vacuole

28. Which of the following is ture of the organic molecule depicted here?

Phaces

(A) It is hydrolyzed to from glycerol.

(B) It represents the building block of a type of protein.

(D) It represents a polysaccharide.

(E) It is acted upon by the enzyme maltase.

29. In a nephron of the kidney, reabsorption of glucose generally takes by the process of

(A) Osmosis

(B) Diffusion

(D) Passive transport

(E) Cyclosis

30. Which of the following plants is a member of the legume family?

(A) Queen anne’s lace

(B) Clover

(D) Buckewheat

(E) Corn

31. The expression “Rh negative” refer to

(A) Immunity to rheumatic fever

(B) Susceptibility to rheumatic fever

(D) A tropism

(E) A rootlike structure of a minus strain of mold

32. Digestive enzymes that hydrolyze molecules of fat into fatty acid and glycerol molecules are known as

(A) Lactases

(B) Lipases

(D) Lipids

(E) Lacteals

33. Which of the following conditions is NOT essential in a self-sustained ecosystem?

(A) A means to permit the cycling of carbon between living organisms and their environment

(B) A means to permit the cycling of water between living organisms and their environment

(D) A living system capable of incorporating energy into organic compounds

(E) Equal numbers of plants and animals

34. The Hardy-Weinberg principle is a mathematical formulation that explains why gene frequencies can remain constant from generation to generation, under certain condition. The fact that gene frequencies in a given population remain constant would be an indication that

(A) Evolution within the population would not take place

(B) Evolution would take place but at a very slow rate

(D) Dominant characteristics would increase in the population and would eventually replace the dominant ones

(E) Recessive characteristics would increase in the population and would eventually replace the dominant ones

35. It is generally believed by scientists that chlorophyll and haemoglobin have a common origin. What is the best reason for believing this to be true?

(A) All organisms contain either chlorophyll or haemoglobin

(B) Heterotroph aggregates have the same basic structure as chlorophyll and haemoglobin

(D) Both substances perform the same biological function

(E) The two substances are similar in chemical structure.

36. The concentration of carbon dioxide in the atmosphere remains relatively constant about 0.04 percent as a result of established equilibrium between the processes of

(A) Assimilation and excretion

(B) Oxidation and photosynthesis

(D) Photosynthesis and reproduction

(E) Respiration and reproduction

37. Which of the following could be expected to cause competition among the chipmunk population in a certain area to increase?

(A) A temporary increase in the chipmunk reproduction rate

(B) An epidemic of rabies among the chipmunks

(D) An increase in the number of hawks that prey on chipmunks

(E) An increase in secondary consumers

38. Which of the following human disorders is caused by a dietary lack?

(A) Haemophilia

(B) Phenylketomuria (PKU)

(D) Sickle-cell anemia

(E) Tay-Sachs disease

39. The methods of agriculture used by humans have created serious problems with insects., chiefly because these methods

(A) Increase soil erosion

(B) Provide concentrated areas of food for insects

(D) Make it possible to grow crops in former desert areas

(E) Encourage insect resistance to their natural enemies

40. Under natural conditions large quantities of organisms matter decay after year’s plant growth has been completed. Which of the following occurs as a result?

(A) Many plants are deprived on adequate food spplies

(B) Many animals are deprived of adequate food supplies

(D) Soils maintain their fertility

(E) Decomposers are placed at a disadvantage in the food chain they are part of .

41. Hawks are useful to the farmer because they

(A) Eat only sickly chickens.

(B) Scare crows away from cornfields

(D) Eat harmful insects

(E) Keep other birds from eating useful crops

42. After surgical operation, which one of the following substances produced in the body is directly responsible for the rejection of a transplanted or such as the kidney?

(A) Amylase

(B) Antibodies

(D) Antigens

(E) Asters

43. In the accompanying pedigree of a family, brown eye color (B) is iindicated as O, and blue eye color (b)as O. From this chart it can be determined that

Phaces

(A) Robert has the same genotype as his grandmother, Mary

(B) Robert has the same genotype as his father, James.

(D) Alice has the same genotype as her father, James

(E) Alice has the same genotype as her grandmother, Mary.

44. The complete oxidation of one molecule of glucose be summarized in the following two equations:

1. glucose +2 ATP + enzymes-à 2 pyrovic acid + 4 ATP

2. pyruvic acid + O₂ + enzymesà CO₂ +H₂O + 34 ATP

it is the net gain of ATO molecules?

(A) 2

(B) 4

(D) 36

(E) 38

45. ...

46. When crossing-over occurs during meiosis, the result is that

(A) The chromatids nonhomologous chromosomes twist about each other

(B) The chromatids thicken and stay apart

(D) Genes are rearranged, increasing the variability of the next generation

(E) Genes are replicated exactly to produce offspring identicall to the parents

47. Which activity is NOT part of the process of DNA replication?

(A) Adenine bonds with thymine

(B) Hydrogen bonds are broken

(D) Nitrogenous base pairs are formed

(E) A double-stranded molecule unwinds

48. Most of the food and oxygen in the environment is produced by the action of

(A) Heterotrophic organisms

(B) Autotrophic organisms

(D) Aerobic bacteria

(E) Archae bacteria

49. The most northern biome on earth is known as

(A) Taiga

(B) Grassland

(D) Temperate deciduous forests

(E) Tundra

50. Which one of the following concepts is NOT associated with the work of Gregor Mendel?

(A) Dominant traits

(B) Recessive traits

(D) Segregation

(E) Independent assortment

51. During experiments dealing with inheritance in plants, paper bags placed over flowers to

(A) Keep them from billowing away

(B) Keep them warm

(D) Keep stray pollen away

(E) Prevent self-

52. The part of the nervous system that controls the contractions of cardiac muscles is the

(A) Autonomic nervous system

(B) Somatic nervous system

(D) Double ventral nerve cord

(E) Cerebrum

53. The action of platelets in the blood breaking apart eadsto the

(A) Dilation of arterioles

(B) Formation of red blood cells

(D) Production of haemoglobin

(E) Production of oxyhemoglobin

54. Which one of the following structures is present in a human nephron?

(A) Urethra

(B) Ureter

(D) Bowman’s capsule

(E) Malpighian tubule

Questions 55-57 refer to the following diagram of the fertilization

Pheces

55. Which structure will develop into the fruit

(A) 1

(B) 5

(D) 8

(E) 9

56. After fertilization, the embryo of the seed is formed by

(A) 3

(B) 4

57. After fertilization, the food of the seed is formed by

(A) 4

(B) 5

(D) 7

(E) 8

Questions 58--60

Direction: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits each statement and then blacken the corresponding space on the answer sheet. A choice may be used once,more than once or not at all in each set.

(A) Adrenal gland

(B) Thyroid gland

(D) Pituitary gland

(E) Small intestine

58. A man is very thin, very active, and has bulging eyes

59. A boy who is being chased by a bully never ran so fast

60. The fat lady of the circus weighs 300 pounds.

Part B (Questions 61-80)

61. Scientists estimate that the earth was formed bout 4.6 billion years ago. A 12-month calendar used to represent the earth’s history would show the following equivalent dates:

January 1 ---- The eawrth forms

April 30 ---- Earliest life appears

November 29 --- First land plants

December 18 ---- Reptiles dominant

December 27 ---- Mammals abundant

December 31 ---- About 10 P.M. --- Humans appear

On the basis of this calener, which one of the following statements as correct?

(A) The heterotrophy hypothesis went into effect on January 2

(B) (B) Molecules of DNA appeared on January 3

62. The correct order of molecules involved in protein synthesis is

(A) Messenger RNA >>> transfer RNA >>> DNA >>> polypeptide

(B) DNA >>> messenger RNA >>> polypeptide >>> transfer RNA

(D) DNA >>> messenger RNA >>> transfer RNA >>> polypeptide

(E) Messenger RNA >>> DNA>>> transfer RNA >>> polypeptide

Question 63-65

The molecular structure of the sugars of DNA and RNA can be represented as follows:

DNA Sugar RNA Sugar

63. The chief difference in the sugar molecules of DNA and RNA is that

(A) One atom of oxygen is missing from the RNA sugar

(B) One atom of oxygen is missing from the DNA sugar

(D) A ribosome is missing in the DNA sugar

(E) A ribosome should be present in both sugar

64. The sugar of RNA is called

(A) Glucose

(B) Sucrase

(D) Ribose

(E) Dextrose

65. All of the following nitrogenous bases can be attached to the sugar of DNA . E XCEPT

(A) Adenine

(B) Cytosine

(D) Thymine

(E) Uracil

Question 66-68

Scientists have made a biochemical of five types of proteins found in both humans and chimpanzees. Their findings are summarized in the following table :

66. According to this table, humans and chimpanzees

(A) Have equal amounts of all the proteins

(B) Have equal amounts of the amino acids

(D) Are most similar in their transferring

(E) Are most similar in their cytochrome

67. The largest protein in the list is

(A) Haemoglobin

(B) Myoglobin

(D) Serum albumin

(E) Transferrin

68. The results for cytochrome C lead to the conclusion that

(A) Neither humans nor chimpanzees need it in their respiratory chain

(B) Both humans and chaimpanzees differ in their amino acis for this protein

(D) Fossils for humans and chimpanzees have identical DNA

(E) Humans and chimpanzees have indentical haemoglobin

Question 69-71

The following drawing of the fluid mosale model of the cell membrane depicts the approximate location of the cell’s molecular activity involved in the sodium potassium pump.

69. All of the flowing statements about the sodium potassium pump are true EXCEPT

(A) It requires AT as the energy source.

(B) It is an example of active transport.

(D) It results in a lower concentration of sodium ions outside the cell.

(E) It results in a lower concentration of sodium ions within the cell.

70. The Sodium potassium ump is located in

(A) A protein molecule of the cell membrane

(B) A lipid molecule of the cell membrane

(D) An ADP molecule of the cell membranes

(E) The cytoplasm itself

71. The action of the sodium potassium pump results in

(A) A movement of ions against the concentration gradient

(B) A movement of ions in a direction equal to the concentration gradient

(D) The exchange of equal numbers of sodium and potassium ions.

(E) The addition of phosphate groups to the ATP molecule

Question 72-74

The molecular composition of the biochemical reaction is represented below:

72. Molecule X can best be described as a

(A) Disaccharide

(B) Monosaccharide

(D) Dipeptide

(E) Diploploda

73. The bond that exists between methronine and phenylalanine is known as

(A) A phosphate bond

(B) A weak hydrogen bond

(D) An ionic bond

(E) A nucleotide bond

74. The reaction shown in the diagram is known as

(A) Hydrolysis

(B) Dehydration synthesis

(D) Photolysis

(E) Carbon fixation

Questions 75-77

Early evidence that DNA is the genetic material of life was derived from experiments with pneumococcus bacteria. A particular strain (S) causes pneumonia in nice. A particular strain (R) does not give them pneumonia. A scientist conducted that flowing experiments:

1. He injected strain S into mice.

2. He injected strain R into other mice.

3. He killed strain S with heat and injected it into mice; they lived.

4. He injected a mixture of dead strain S and living strain R into mice. They died of pneumonia. Blood samples now showed the presence of live S bacteria.

5. He grew strain S on a culture medium, killed it with heat, ground it up, and prepared an extract which he then mixed with live strain R. He injected this into moice. They died of pneumonia; their blood now contained live S bacteria.

6. Conclusion: Hereditary material, later indentified as DNA, from the dead S bacteria entered the living R bacteria, changing them into S bacteria.

75. In experiment 1, it was observed

(A) The mice caught pneumonia from strain R

(B) The mice remained healthy

(D) The mice died of pneumonia

76. In experiment 5:

(A) By evolution, the DNA of strain R became changed and no longer caused pneumonia.

(B) Strain S extract contained living pneumococcus bacteria.

(D) The S extract plus strain R casued pneumonia.

(E) Although strain S was killed by heat, it still caused pneumonia without strain R.

77. The change in the heredity of the strain R casued by DNA of strain S is known as

(A) Nucleic acid

(B) Transformation

(D) Transmission

(E) Extraction

Questions 78-80

Scientists conduced an experiment to try to increase the oil content of corn seeds. They planted corn for a total of 50 generations. Each time they had a crop, they selected only seeds with a high oil content for planning. The summarized their results in the following graph:

phaces

Based on this inforatiom, select the best answer to each of the following question:

78. At the end of the expleriment, the percent of oil in corn seeds.

(A) Increased by 50 percent

(B) Increased from 5 to 15 percent

(D) Remained unchanged because of fluctuating weather conditions

(E) Remained unchanged because corn seeds contain very little oil

79. The best explanation for the results is

(A) Darwin’s theory of natural selection

(B) Lamarck’s theory of use and disuse

(D) A series of mutations in the genes

(E) Mendels’s law of independent assortment

80. To prove that a new species of corn had been produced after 50 generations, it would be necessary to show that.

(A) Geographic isolation had been established

(B) The chromosome number remained the same

(D) Recombinant DNA had been produced

(E) The new individuals could not be crossed with the original type.

Answer Key

1. (D) 31. (C)

2. (A) 32. (B)

3. (E) 33. (E)

4. (C) 34. (A)

5. (C) 35. (E)

6. (C) 36. (B)

7. (D) 37. (A)

8. (B) 38. (C)

9. (B) 39. (B)

10. (C) 40. (D)

11. (D) 41. (C)

12. (A) 42. (B)

13. (E) 43. (D)

14. (D) 44. (D)

15. (C) 45. (A)

16. (C) 46. (D)

17. (B) 47. (C)

18. (A) 48. (B)

19. (D) 49. (E)

20. (B) 50. (C)

21. (B) 51. (D)

22. (E) 52. (A)

23. (E) 53. (C)

24. (C) 54. (D)

25. (E) 55. (D)

26. (B) 56. (C)

27. (D) 57. (C)

28. (E) 58. (B)

29. (C) 59. (A)

30. (B) 60. (B)

61. (D)

62. (D)

63. (B)

64. (D)

65. (E)

66. (E)

67. (E)

68. (C)

69. (D)

70. (A)

71. (A)

72. (D)

73. (C)

74. (A)

75. (E)

76. (D)

77. (B)

78. (B)

79. (C)

80. (E)

Answer Explained

1. (D) Darwin stated that the organism that possessed favourable variations would be most fit in the struggle for existence, and would survive. The lower forms of life are broadly adapted to the conditions surrounding them, and have continued to survive.

2. (A) A ribosome is a tiny granule located on the endoplasmic reticulum of the cytoplasm. It is the place where amino acids are bonded together to synthesize proteins.

3. (E) Monocotylendons are flowering plants in which fertilization occurs internally within the oviduct, following the introduction of sperm during mating.

4. (C) In amniocentesis a doctor removes a small sample of amniotic fluid from the uterus of an expectant mother. This liquid surrounds the developing fetus and contain cells that are normally shed by it. The presence of an extra chromosome pair 21 may lead to Down syndrome, in which there is mental and physical impairment.

5. (C) RNA differs from DNA in having the base Uracil (U) instead of thymine (T). In RNA, cytosine (C) bonds with guanine (G), and adenine (A) bonds with Uracil (U) instead of with thymine (T).

6. (C) Neurons are not directly connected with each other. Impulses pass from the end brush of the axon of one neuron to the dendrites of another across the area of a synapse.

7. (D) The adrenal gland is located at the top of the kidney.

8. (B) the dinosaurs were giant reptiles that dominated the earth during the Mesozoic Era.

9. (B) As the result of being isolated, any changes that occurred among the finches of one island remained concentrated there. These birds did not interbreed with those from other islands, and remained distinct from them.

10. (C) Insulin permits the cell to use glucose for energy. In diabetes, where there is a shortage of insulin, the glucose remains unused and is excreted as waste.

11. (D) a paramecium moves forward until it but into an object. Then it reverses the movers of its cilia, backs up, and moves forward at a different angle. In this way, it can at obstacles in its way. At other times, it reverses its movement and goes off in a pletely different direction.

12. (A) The grasshopper breathes by a system of to that connect with the openings, or spiracle its abdomen. Air is pumped in and out of tubes by the contractions and expansion the abdomen.

13. (E) The chestnut blight is a parasitic fungus began destroying chestnut trees at the beginning of this century by now there are pr cally no chestnut trees left in the easy United States.

14. (D) The coronary arteries supply the cells of heart with nourishment. A clot blocks the of blood through them and causes a heart .this condition is known as coronary thromb.

15. (C) Stomates are the tiny openings in the ..... of a leaf. The size of the stomatal ........ is controlled by pairs of guard ,,,,,, . water is constantly given of through ,,,, openings during transpiration. During ,,,,,, of dryness, the guard cells reduction size of the openings, thereby avoiding excessive loss of water.

16. (C) In nondisjunction, a pair of homologous mosomes fails to separate during meiosis results in gametes having one chromosomes more or less than the monoploid ,,,,,,, . After fertilization, the new individual more (as in Down syndrome) or less that normal 2n number of chromosomes.

17. (B) In sexual reproduction, many unlike gametes are involved, each having its own gametes makeup. When gametes are brought to the during fertilization, there will be many and combinations of genes, resulting in ,,,, deal of variety in the offspring .

18. (A) The phase microscope uses different atre ments of light waves that are out of phase each other, resulting in variations it intensity. This makes possible the exams of normal living cells without the ,,,,, staining them

19. (D) The possible genetic combinations would be:

Key:

X= Chromosome containing normal gene

X= chromosome containing gene haemophilia

Female: 50% normal homozygous

50% normal hheterozygous

Male: 50% normal;

50% haemophiliac

20. (B) By chance, a 1:2:1 ratio is generally obtained then large numbers are involved. With small numbers, the results are not predictable because they may tend to concentrate in one particular area.

21. (B) Anaerobic respiration, also referred to as fertilizentation, takes place in the absence of oxygen. The only yield of enerhy is 2 ATPs. There is still a great deal of energy stored in ,,,, acid alcohol molecules, where the H-C and C-H bonds remain intect

22. (E) ingwarm is a parasitic fungus infection of the skin, not a worm.

23. (E)Bacteria are single-celled members of the ,,,,,, kingdom; paramecia are members of the Protista kingdom; yeasts are members of the Fungi kingdom.

24. (C)The millimetre contain 1,000 micrometers. Therefore, 0.6 mm contains 600 micrometers (1,000 x 0.6 ).

25. (E)DNA is produced in the nucleus and carries in a genetic code for the formation of proteins and the ribosomes, where amino acid are ,,,,,,, into proteins

26. (B)

27. (D) The ribosome is a tiny granule found in the endoplasmic reticulum of the cell. It contains first of the RNA of the cell and is the site of

28. (E) The structural formula of the disaccharide maltose is shown. It is a polymer of two glucose units. Under the influence of the enzyme maltase, it is hydrolyzed and converted into glucose

29. (C) The reabsorption of glucose and other materials takes place by active transport. Energy is released by the mitochondria of the nephron to move the glucose molecules through the membrane back into the bloodstream. This movement is opposite to that which would normally occur through diffusion.

30. (B) Other members of the legume family are alfalfa, peanut, bean, and pea. These plants have nodules on their roots containing nitrogen-fixingbacteria. Their fruit is usually in the form of a pod.

31. (C) About 15% of the population has the Rh-negative blood type.

32. (B) lipases are digestive enzymes that break down the relatively large molecules of fat into smaller molecules of fatty acid and glycerol.

33. (E) An ecosyslem is a community of plants and animals that are self-sustaining in relation to their physical environment. In order to be self-sustaining, the community requires autotrophic orhanisms as its basis. These make their own food, using the constant source of energy available in the sun. The various cycles, such as carbon, water, and nitrogen, help yo make the important elements available for the use of the organisms. As a result, matter and energy are constantly being exchanged between the community and the physical environment. Equal numbers of plants and animals are not significant in these relationships.

34. (A) According to the Hardy-Weinberg principle, gene frequencies remain constant from generation to generation if mating is at random, and no new factors are introduced, such as mutation, selection, or migration. Under such theoretical conditions, the species would remain predictablythe same.

35. (E) Hemoglobin is closely related, chemically, to chlorophyll. However, the hemoglobin molecules contains iron, while the chlorophyll molecules contains magnesium. Both substances belong to a class of pigments known as porphyrins. According to the heterotrophy hypothesis, primitive protein molecules may have developed, leading to porphyrin molecules that served as a common origin for

36. (B) During oxidation, living things take in oxygen and give off carbon dioxide and water as wastes. During photosynthesis, carbon dioxide and water are taken in by green plants and oxygen is given off as a waste. As a result the concentrations of carbon dioxide and oxygen in the atmosphere remain relatively constant.

37. (A) A temporary increase in the chipmunk reproduction rate would cause am increase in the number of chipmunks seeking food in the given area. This wuld result in increased competition among them for the available food and other necessities of life.

38. (C) Pellagra is a nutritional disorder caused by lack of the vitamin niacin.

39. (B) Insect are the greatest enemies of human. Although other forms of life have had difficulty maintaining themselves with the spread of civilization, incects have continued to multiply and spread. Humans have promoted this growth of insects by planting crops in large fields, thereby providing the insects with concentrated areas of food. The potato beetle and the corn borer, for example, do not have far to go for their food once they settle in the right field.

40. (D) The organic material in plants is attacked by bacteria of decay and by fungi. The protein compounds are digested by them and broken down first into amino acids, and them into simpler nitrates and other compounds. Thus the fertility of soils is maintained.

41. (C) The hawk is a carnivorous bird that is useful because it destroys more rodents than eat grain.

42. (B) The transplanted organ from another person may act as an antigen and stimulate antibodies to attack it, causing the organ to be rejected by the recipient’s body. Specifically, T cell antibodies are involved. A doctor may prescribe the drug cyclosporine to suppress the immune reaction of these antibodies.

43. (D) James is heterozygous for brown eyes, since he received a gene for blue eyes from his father, John and a gene for brown eyes from his mother, Mary. James’s daughter Alice is

44. (D) According to the first of the two equations, glucose is broken down by enzymes to yield 4 molecules of ATP. However, in order for some of the process to occur, the energy from 2 ATP was used up. As a result, the total gain of energy during this phase is only 2 ATP molecules. The next equation shows the breakdown of pyruvic acid as uielding 34 ATP. The net gain of both equations is thus 2 + 34=36 ATP.

45. (A) Abiotic factors are the nonliving influences in the environment. In addition to soil and stones, these influences could also include light, temperature, water supply, oxygen supply, minerals, and pH.

46. (D) During synapsis, in the first part of meiosis, the chromatids of homologous chromosomes may twist about each other and then separate, exchangeing adjacent parts. As a result sets of genes cross over from one chromosome to another, producing new combinations so characteristics.

47. (C) Ribosomes are either distributed along the endoplasmic reticulum of the cell or are free in the cytoplasm. They contain RNA and function as the site of protein synthesis.

48. (B) Green plants that contain chlorophyll are considered to be autotrophic organisms because they can make their own food by photosynthesis. In the process, they give off oxygen into the atmosphere.

49. (E) Tundra is the treeless region in the most northern biome of the earth. The underlying part of the ground is permanently frozen. During the brief summer, the upper part thaws temporarily and mosses and small plants grow abundantly.

50. (C) Gregor mendel’s paper on his experiments dealing with inheritance in pea plants was first published in 1866, long before the structure of the gene in the DNA molecules was identified in the middle of the 20^th century.

51. (D) By covering the flowers with paper bags, stray pollen is prevented from interducing factors that are not part of the experiment.

52. (A) The autonomic nervous system consists of masses of ganglia located on either side of the backbone and plexuses, which control serval

53. (C) The breaking up of platelets starts a sries of reaction that ends in the formation of a clot. At the beginning, the enzyme thromboplastin is given off, which causes prothrombin to change into thrombin. This acts on fibrinogen to produce threads of fibrin. Red blood cells become entangled in the resulting network, and a clot is formed.

54. (D) Blood vessels in the kidney branch into a network of capillaries called the glomerulus, which is surrounded by a thin-Walled cup, known as Bowman’s capsule, that extends into a long nephron tubule.

55. (D) Ovary

56. (C) Egg nucleus

57. (C) Endosperm nuclei

58. (B) The man undoubtedly is suffering from an overactive thyroid gland. As a result of the extra amount of thyroxin, his metabolism is carried on at a faster rate.

59. (A) During times of emotional stress, such as the boy is experiencing a greater amount of adrenaline is increased amount of glucose and oxygen to be brought to the muscles, supplying them with additional energy.

60. (B) In obesity, the thyroid gland is underactive resulting in a lower metabolism rate. Food is not entirely oxidized, and the excess is stored as fat.

61. (D) Mammals became abundant during the present Genozoic era after the dinosaur, which had predominated during the earlier Mesozoic era had died out.

62. (D) A part of a DNA molecule, which is a gene serves as a template or pattern, for the synthesis of a messenger RNA molecule. This mRNA now carries the genetic code, which consists of triplets of nucleotides called condons. The new mRNA leaves the nucleus, enters the cytoplasm, and becomes located in a ribosome. Here, small transfer RNA molecules (tRNA) which picked up with mRNA. The tRNA has a group of three molecules called an anticodon, which fits the appropriate condon on the mRNA. The tRNA separates when mino acid molecules are linked together to from a polypeptide.

63. (B) DNA represents deoxyribonucleic acid, ind cating that its five-carbon sugar is deoxyrbose. The de prefix means that it is missing a oxygen atom. By comparison. RNA has five-carbon ribose sugar that contains an additional oxygen atom.

64. (D) As explained in the previous answer, the RNA molecules contains a five-carbon ribose sugar. This is different from the deoryribose sugar on DNA which has one oxygen atom less.

65. (E) RNA contains the same bases as DNA namely adenine, cytosine, and guanine, exceptfor uracil which takes the place of thiamine.

66. (E) This table shows that there are no amino acid differences in cytochorome of human s and chimpanzees, thus making it the most similar of the proteins in the list.

67. (E) The table shows that there are 647 amino acids in transferring, the largest number of any of the proteins listed.

68. (C) Biochemical tests of protein similarities between humans and chimpanzees indicated that chimpanzees are the closest relatives to humans. The study of cytochrome c, a protein that functions in cellular respiration, shows that it is identical for the two species and that there are no amino acid differences in this protein between them. This is part of large body of evidence indicating that humans and chimpanzees probably descended from a common ancestor during their evolutionary history.

69. (D) The action of the sodium-potassium pump results in the passage of sodium ions out of the cytoplasm into the exterior of the cell where there is a higher concentration of sodium ions. This is against the concentration gradient and requires energy, which is supplied by ATP. This is an example of active transport.

70. (A) According to the fluid Mosaic model, the cell membrane consists of two layers of lipid molecules in which proteins are cmbedded both on the surface and in the interior of the membrane. During the action of the sodium potassium pump a protein molecules become activated by ATP. It transports sodium ions out of the cell and potassium ions into the cell.

71. (A) As a result of the action of the sodium-potassium pump, sodium ions moved out of the cell to the exterior, where there is a higher concentration of sodium ions. Also potassium ions are moved from the exterior of the cell into the cytoplasm, resulting in a higher concentration of potassium ions. In both cases, ions are moved from a region of low concentration to a region of higher concentration gradient and requires the energy of ATP.

72. (D) A dipeplide consists of two molecules of amino acids, such as ILE and TYR, that combine by forming a bond between the amino group (-NH₂) of one and the acid group (-COOH) of the other.

73. (C) When two amino acids are combined they form a bond between the amino group of one and the acid group of the other. The amino group loses an atom of hydrogen and an atom of oxygen. The hydrogen atoms combine with the oxygen atom to form a molecules the two amino acids and the water splits off.

74. (A) During the chemical process of hydrolysis a large protein molecule is split into smaller protein molecules by adding water. Digestive enzymes speed up hydrolysis.

75. (E) In experiment (1), mice were injected with strain S pneumococcus bacteria. This strain of bacteria caused pneumonia, and the mice died of the diseasw.

76. (D) In experiment (5), strain 5 bacteria were grown on a culture medium. They were then killed by heat and ground up. An extract of the dead bacteria was prepared and mixed with live strait R which is normally harmless. However, in this case, the mice died of pneumonia. Under the microscope, their blood was seen to contain strain S bacteria.

77. (B) Transformation is the transfer of DNA dead bacteria into living bacteria, as was in experiments (4) and (5). The result was the heredity of harmless strain R bacteria became changed into harmful strain S bacteria.

78. (B) The graph shows that the oil content of corn seeds at the beginning of the experiment was 5 percent, and at the end. 50 genera later, it had risen to 15 percent.

79. (C) As the seeds with the highest on content selected for planting in each generation gene combinations for low oil content steadily being eliminated. By such selected greater concentration of gene combination high oil content resulted after 50 generation. It is unlikely that mutations, which are and random, could have resulted in the increase in oil content for 50 generations.

80. (E) Although the members of a particular share the same gene pool, they may be much variation from each other in their acteristics. However, if they cannot represents with another group, even though they appear similar, then they are considered a different species. In this experiments individual corn plants continued to represent and yiels seeds with a higher oil content establishing that they were still membrane the same species.

14^TH DIAGNOSTIC TEST

PART A

Directions: Each question or incomplete statement below is followed by five possible answers or completions, lettered A—E. Choose the answer that is the best in each case. Fill in the corresponding oval on your answer sheet.

1. Which of the following is found in all forms of life?

I. Genetic material

II. Protein

III. Water

(A) I only

(B) II only

(D) I and III

(E) I,II, and III

2. Which of the following is NOT essential for blood clotting?

(A) Sodium ions

(B) Calcium ions

(D) Vitamin K

(E) Platelets

3. Which substance does NOT act as a digestive enzyme for proteins?

(A) Pepsin

(B) Trypsin

(D) Chymotrypsin

(E) Gastrin

4. Which of the following is a function of bone?

I. Formation of blood cells

II. Protection of vital organs

III. Framework for movement

(A) I only

(B) II only

(D) I and II

(E) I, II, and III

5. The hypothesis that chloroplasts and mitochondria were originally prokaryotic organisms living within eukaryotic hosts is supported by tha fact that mitochondria and chloplasts

I. Possess protein synthetic capability

II. Possess genetic material

III. Possess a lipid bilayer membrane

IV. Possess characteristic ribosomes

(A) II only

(B) IV only

(D) III and IV

(E) I,II, and IV

6. A culture of white blood cells is grown on a nutrient media with glucose containing a poison that block the electron transport chain. Under these conditions, if the cells grow at the same rate as cells without toxin

(A) ATP production will remain the same

(B) Glucose consumption will increase

(D) Ethanol production will increase

(E) None of the above

7. Many animals use panting as means of cooling themselves down. The mechanism behind panting is to

(A) Rapidly increase carbon dioxide expiration

(B) Moisten the mucosa of the respiratory passages

(D) None of the above

8. Glucose in the glomerular filtrate is partially resorbed in the

(A) Bowman’s

(B) Glomerular

(D) Villi

(E) Ureter

9. Which are correctly related?

(A) White blood cell: no nucleus

(B) Smoothe muscle cell: multinuclear

(D) Cardiac muscle: involuntary action

(E) Smooth muscle: striation

10. A process that cannot take places in a haploid cell is

(A) Mitosis

(B) Meiosis

(D) DNA replication

(E) Transcription

11. To test whether a tall plant ( in which the tallness allele is dominant and short allele is recessive ) is homozygous or heterozygous you could

I. Cross it with a tall plant that had a short parent

II. Cross it with a tall plant that had two tall parents

III. Cross it with a short plant

(A) I only

(B) II only

(D) I and II

(E) I and III

12. Strontium is preferentially incorporated into growing long bone. Therefore, if a child were exposed to strontium most likely be found?

(A) In the cartilage lining the joints

(B) In the center of long bones

(D) Near the epiphyseal plates of long bones

(E) Evenly distributed throughout the body

13. Venous blood en route from the kidneys to the heart must pass through the

(A) Iliac vein

(B) Inferior vena cava

(D) Hepatic vein

(E) Pulmonary vein

14. Humans cannot produce Vitamin K. However, even when their diet is lacking in Vitamin K, they have plenty of it in their bloodstream. How can this be possible?

(A) Vitamin K is synthesized in the liver using hormones absorbed from ingested plant cells

(B) Vitamin K is a byproduct of protein degradation during digestion.

(D) Vitamin K can be produced by exposure to sunlight.

(E) None of the above

15. The bicarbonate ion in the digestive tract

(A) Neutralizes stomach acid

(B) Promotes phagocytosis by white blood cells

(D) Functions in the blood clotting mechanism

(E) None of the above

16. Which of the following in NOT characteristic of fermentation?

(A) It is anaerobic.

(B) It requires glucose.

(D) It requires oxygen

(E) It plroduces ethanol

17. If a tracer substance is injected into a patient’s superior vena cava, which of the following structures would the tracer reach last? .

(A) The right ventricle

(B) The left ventricle

(D) The left atrium

(E) The right atrium

18. Which of the following is the pacemaker of the heart?

(A) The foramen oval

(B) The sinoatrial node

(D) The burridle of his

(E) The vagus nerve

19. If a diabetic accidentally overdosed on insulin, which of the following would be likely to occur?

(A) Increased levels of glucose in the blood

(B) Increased glucose concentration in urine

(D) Increased conversion of glycogen to glucose

(E) Increased converstion of glucose to glycogen

20. The best description of indentical twins is that they are

(A) Twins of the same sex

(B) Wtins from a single egg

(D) Twins from two single egg fertizlied by two separate sperm

(E) Twins from a single egg fertilized by two separate sperm

21. Which of the following lacks vertebrae?

(A) The duckbill platypus

(B) The turtle

(D) The trout

(E) The rabbit

22. Ingestion of the insecticide Parathion, which blocks acetylcholinesterase function, would cause

(A) A decrease in postsynaptic signals

(B) A halt to all synaptic nervous transmissions

(D) A decrease in acetylcholine concentration in synapses

(E) Levels of acetylcholine to remain the same

23. Straight tail (T) is dominant over bent tail (t) in mice, and long-tailed mice (L) are dominant over short-tailed mice (l). Which cross must produce all straight, long-tailed mice?

(A) TtLl x TtLl

(B) Ttll x TTLl

(D) TtLl x TTLL

(E) None of the above

24. In adult humans, red blood cells

(A) Have no nucleus

(B) Are replaced in the liver

(D) Are made in the spleen

(E) Are the sites of rapid protein synthesis

25. The notochord is

(A) Present in all adult chordates

(B) Present in all echinoderms

(D) Always a vestigial organ in chordates

(E) Part of the nervous system of all vertebrates

26. A typical human gamete

(A) Contains a haploid number of genes

(B) Will always contain an X or a Y chromosome

(D) Has undergone genetic recombination

i. I and II

ii. I and III

iii. II and III

iv. II, III and IV

v. I, II and IV

27. The absorption of oxygen from the atmosphere into the blood takes place in the

(A) Pulmonary artery

(B) Pulmonary vein

(D) Trachea

(E) Bronchi

28. Which of the following is a substance secreted by a member of a species that affects other members of the same species?

(A) Gender-spedific proteins

(B) Lacrimal fluid

(D) Hormones

(E) Pheromones

29. The rate of breathing is controlled by involuntary centers in the

(A) Cerebrum

(B) Cerebellum

(D) Spinal cord

(E) Hypothalamus

30. Enzymes in human cells

i. Are proteins

ii. Typically work best at pH 7.2

iii. Are changed during a reaction

iv. Are found in the nucleus only

A. I only

B. II only

C. I and II

D. I, II and III

E. I,II,III and IV

31. Which of the following occurs in the cell nucleus?

i. RNA synthesis

ii. Protein synthesis

iii. DNA synthesis

A. I only

B. II only

C. III only

D. I and III

E. I, II and III

32. Which statement about the plasma membrane is false?

(A) It serves as a selectively permeable barrier to the external environment.

(B) It serves as a mediator between the internal and external environments.

(D) It contains phospholipids as a structural component.

(E) It contains proteins that in some cases span the membrane.

33. Which of the following is a type of genetic mutation?

(A) Point

(B) Silent

(D) Frameshift

(E) All of the above

34. Pancreactic exoxrine secretions contain all of the following EXCEPT

(A) Proteases

(B) Lipases

(D) Glucagon

(E) Bicarbonate ions

Questions 35-38 refer to the figure of the vascular system of a plant below.

35. Which structure is responsible for the transport of nutrients?

(A) 2

(B) 3

(D) 5

(E) 6

36. Which structure is responsible for the transport of water and minerals?

(A) 2

(B) 3

(D) 5

(E) 1

37. Which structure is made up of rapidly dividing, undifferentiated cells?

(A) 2

(B) 3

(D) 5

(E) 6

38. Which structure is used to support the plant

(A) 4

(B) 5

(D) 7

(E) 8

Part B

Each set of choices A_E below should be compared to the numbered statements that follow it. Choose the lettered choice that best matches each numbered statement. Fill in the correct oval on your answer sheet. Remember that a choice may be used once, more than once, or not at all in each set.

Questions 39-42

(A) Virus

(B) Bacteria

(D) Planaria

(E) Sponge

39. May contain plasmid DNA

40. Has a cell membrance but lacks a true nucleus

41. Genetic material can be either DNA or RNA

42. Bilaterally symmetrical

Questions 43-47

(A) Glycolysis

(B) Fermentation

(D) Electron transport chain

(E) Photosynthesis

43. Utilizes a proton pump

44. Occurs in the mitochondrial matrix

45. Is an a naerobix process that forms NAD

46. Occurws in the inner membrance of the mitochondria

47. Creates byproducts of ethanol or lactic acid

Questions 48-51

(A) Musculoskeletal system

(B) Endocrine system

(D) Nervous system

(E) Reproductive system

48. Transports respiratory gases, nutrients, and wastes

49. Enables organisms to receive and respond to stimuli

50. Is an internal structural framework

51. Performs internal communication through the circulatory system and coordinates the activities of the organ systems.

Questions 52-55

(A) Adenine

(B) Guanine

(D) Cytosine

(E) Uracil

52. Purine that binds with three hydrogen bonds

53. Found only in RNA

54. Pyrimidine that binds with three hydrogen bons

55. Purine found in both DNA and RNA that binds with two hydrogen bonds

PART C

Each of the following sets of questions is based on a laboratory or experimental situation. Begin by studying the description of each situation. Nest, choose the best answer to each of the questions that follow it. Fill in the corresponding oval on your answer form.

A stable population exists in Hardy- Weinberg equilibrium with two alleles, T and t. TT and Tt individuals have the ability to curl their tongues, while tt individuals cannot curl their tongue. The allele frequency of T is 0.8.

The data above will help you answer questions 56-58.

56. What is the allele frequency of t?

(A) 0.04

(B) 0.2

(D) 0.16

(E) 0.64

57. What is the percentage of heterozygotes?

(A) 4 %

(B) 32%

(D) 50%

(E) 75%

58. What is the percentage of individuals that can curl their tongues?

(A) 32%

(B) 4%

(D) 96%

(E) 50%

A scientist grew her bacterial colonies in variety of different concentrations of nutrients to determine at which concentration they grew best. The results of her experiments are summarized in the following bar graph.

phacrs

Now answer question 59.

59. What is the optimum concentration of nutrient supplement?

(A) 10U/mL

(B) 20U/mL

(D) 40U/mL

(E) 50U/mL

A mouse was put in a maze and timed to determine how long it took him to find the food pellet at the end. A total of eight trails were done unti the researchers were confident that the mouse had learned the maze. The date follows in both tabular form in the table and graphical form.

phaces

Trial Number Number of Seconds

1 40

2 20

3 25

4 16

5 17

6 10

7 12

8 10

60. The greatest improvement is shown in the

(A) First trial

(B) Second trial

(D) Fourth trial

(E) Fifth trial

ECOLOGICAL SECTION

(if you are taking the Molecular Section, go to Question 81).

Questions 61-64 refer to the following tables of climate data.

phaces

61. Station B is most likely located in which biome?

(A) Taiga

(B) Tropical rainforest

(D) Tundra

(E) Estuary

62. Coniferous forests are most likely to be found at which station?

(A) A

(B) B

(D) D

(E) E

63. Primary productivity is likely to be lowest in the biome of which station?

(A) A

(B) B

(D) D

(E) E

64. The population of freshwater clams in a large lake has declined steeply in recent years. When scientists tested the lake’s waters, they discovered that the lake had become more stratified and the bottom layers had become significantly saltier. Which station is most likely to be located near this lake?

(A) A

(B) B

(D) D

(E) E

65. Which of the following would NOT affect the environmental resistance of an ecosystem dominated by prairie dogs?

(A) Homes are built on nearby bluffs that had been home to several species of raptors.

(B) Prairie dogs can produce litters of up to 6 pups, which are cared for under ground by parents for 6 weeks.

(D) Severe flooding destroys burrows and drowns new-born pups.

(E) The population of black-footed ferrets, which live in prairie dog burrows, increases due to legal protections.

66. Lake eutrophication may result in any of the following effects EXCEPT:

(A) A secchi disk lowered into the lake indicates a shallower photic zone.

(B) Zooplankton population decline due to low dissolved oxygen (DO₂) levels.

(D) The grows shallower as undecom posed organic matter accumulates in anoxic bottom layer.

(E) Fish egg are smothered on the lake bottom, reducing fish population.

67. Which of the following is / are likely to result in more PO₄ ^3- being available to primary producers

I. Burying beetles find a mouse carcass and lay eggs near it after burial

II. In a forest, an, elk is killed and partially eaten by wolves.

III. Thick moss mats develop on bare rock to serve as anchorage for larger plants.

(A) I only

(B) III only

(D) I and III only

(E) II and III only

68. Gypsy moths were brought to the United State about 150 years ago ina misguided attempt to produce silk more cheaply. A few gypsy moth caterpillars were accidentally released in Massachusetts, and within 20 years they had infested local woodlands. Their descendants have since munched their way through forests across most of the country.

Which of the factors listed below did NOT contribute to the success of gypsy moths in their new environment?

(A) Gypsy moths have no indigenous predators.

(B) Gypsy moths evolved over time to be successful in their new environments.

(D) Trees have no natural defences against gypsy moths

(E) Gypsy moths out-competed native species, which could not coevolve with them.

Questions 69-70 refer to the following paragraph:

A volcanic eruption deposits a thick layer of ash over a wide area, bliterating the old landscape. In a field beyond the affected zone, a dandelion flowers and releases its wind-borne seeds, some of which land on the ash. Most do not grow, but two of the dandelions sprout and produce a new crop of seeds

69. Which of the following is/are true of the dandelions in this scenario?

I. Dandelions are a keystone species.

II. Dandelions are a pioneer species.

III. Dandelions are a K-strategist species.

(A) I only

(B) II only

(D) I and III only

(E) I and II only

70. Which of these predictions is LEAST likely to be correct about the years following the dandelion growing on the volcanic ash?

(A) The dandelion population will eventually reach carrying capacity and stabilize.

(B) The dandelions may soon be joined in the devastated area by lichen and mosses.

(D) A graph of the number of dandelion individuals over the next ten years would show an exponential curve.

(E) The dandelions will eventually lose their competitive advantage in the new niche.

71. Which of the following is NOT true of energy flow through ecosystems?

(A) Energy is conserved and stays in an ecosystem, to be used by organisms again and again

(B) Solar radiation is the original energy source for the vast majority of organisms on Earth.

(D) Energy flow is inefficient, a lot is lost in each transfer from one organism to another.

(E) All solar radiation used in photosynthesis will eventually be lost as heat.

72. A hermit crab will often place a sea anemone on its shell, carrying the anemone with it wherever it goes. When the crab outgrows its shell, it finds a larger one to move into, carefully transferring the anemone to the new shell. The crab is protected from predators by the anemone’s stinging tentacles while the anemone eats food particles left by the crab.

This is an example of:

(A) Parasitism

(B) Predation

(D) Commensalism

(E) Competition

73. Decomposers are vital parts of an ecosystem because they:

(A) Release stored energy to be recycled.

(B) Release stored nutrients by breaking down comples organic molecules into thesimple molecules required for primary productivity.

(D) Are autotrophs.

(E) The statement is incorrect; decome posers are NOT a vital part of energy ecosystem.

74. A food chain includes oak trees--à squirrels--àfoxes--àblowflies. Which role is unfilled in this chain?

(A) Secondary consumer

(B) Tertiary consumer

(D) Decomposer

(E) Producer

75. Jewel beetles can breed only in recently-burned wood. What pe of dispersal pattern would most likely be seen in jewel beetles?

(A) Random

(B) Mixed

(D) Uniform

(E) Cannot tell from information given

Questions 76-78 are based on the graph below. Assume that all food species are plants.

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76. Referring to the graph above, which of the following statements is NOT correct?

(A) Rodent density is dependent on food-species diversity

(B) Food-species diversity is dependent on rodent density

(D) Rodents are selective in their food choice

(E) Rodents help prevent food-species monocultures from developing.

77. What effect could a large raptor population be predicted to have on food species diversity and rodent density?

(A) Diversity would increase, density would decrease.

(B) Diversity would decrease, density would increase.

(D) Diversity would decrease, density would decrease.

(E) It is impossible to predict from the information given.

78. In this example, the relationship between food species plants and rodents can characterized as:

I. Density-dependent

II. Predator-prey

III. Niche differentiating

(A) I only

(B) II only

(D) I and II only

(E) I and III only

79. The structure of this age pyramid structure shows that this population is

(A) Stable, because there are plenty of individuals in each age group.

(B) Growing, because there are a large number of adults, who can reproduce.

(D) Declining, because survivorship is below replacement rate.

(E) Declining, because natality is high and mortality is low.

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80. Which statement below is Not true of both the nitrogen and the carbon cycle?

(A) Both cycles keep vital nutrients available to primary producers.

(B) Both nutrients enter and exit the cycle as atmospheric gases.

(D) Both nutrients are crucial components of the amino acids all organisms require.

(E) All of the above statements are true.

MOLECULAR SELECTION

The first step in glucolysis is catalyzed by the enzyme hexokinase. The reaction catalyzed by this enzyme is the phosphorylation of glucose to produce glucose 6-phosphate, with the consumption of one ATP and the production of one ADP. A scientist isolates hexokinase from bovine skeletal muscle and studies its activity in a variety of conditions. In Figure 1, the rate of glucose 6-phosphate production was studied as more enzyme was added, with a constant amount of glucose and ATP added. In Figure 2, the rate of glucose 6-phosphate was studied as more glucose was added to the mixture, with the amount of hexokinase held at a constant amount.

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[Hexokinase] (ug/mi )

Figure 1

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[ Glucose] (uM)

Figure 2

Use this data to answer question 81-83.

81. Which of the following is true of hexokinase?

(A) Hexokinase increase the equilibrium ratio of [glucose 6-phosphate]/[glucose].

(B) Hexokinase increases the rate at which equilibrium is reached, but does not change the equilibrium.

(D) Hexokinase increases the rate until it is consumed, and the reaction ceases.

(E) Hexokinase can only catalyze the forward reaction.

82. If the amount of hexokinase in the mixture is doubled from 1 ug/ml 2 ug/mi, which of the following will occur/

(A) The activation energy of the reaction will be 50 percent lower with 2 ug/mi them with 1 ug/mi.

(B) The rate of ADP production will double.

(D) The rate of glucose 6-phosphate production will increase three-fold.

(E) The rate of glucose 6-phosphate production will be saturated and increase only slightly.

83. If the concentration of glucose in Figure 2 is increased to 6 uM from 3 uM, which of the following be observed?

(A) The rate glucose-6 phosphate production will double, and the rate of ATP consumption will go down.

(B) The rate of glucose-6 phosphate production and ATP consumption will both double.

(D) The rate of glucose-6 phosphate production will remain constant, and ATP consumption will increase.

(E) The rate of glucose-6 phosphate production will remain constant, and the rate of ATP consumption will remain constant.

84. Which of the following is true regarding DNA replication?

I. DNA replication is semi-com-servative.

II. DNA replication occurs during Prophase.

III. DNA synthesis occurs in a 3 to 5 direction.

IV. Purines hydrogen bond to pyrimidines.

(A) I and II

(B) I,II and III

(D) I, II,III and IV

(E) I and IV

85. During the process of oxidative phosphorylation, oxygen serves as

(A) The initial acceptor of electrons

(B) The final acceptor of electrons

(D) A phosphorylating agent

(E) A reducing agent

A researcher grew E. coli bacteria that either had a plasmid ( an extranuclear piece of DNA) or did not have a plasmid. These two types of E. coli were grown in two different growth mediums----a normal nutrient growth medium, and a normal nutrient growth medium with tetracycline, an antibiotic. The results of these experiments are summarized in the following graphs of growth of bacteria versus time.

E.Coli without plasmid

E. Coli with plasmid

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Time(Hours)

Graph 1: Bacteria Growth in Nutrient Media Alone

E.Coli without plasmid

E.Coli with plasmid

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Time(Hours)

Graph 2: Growth of Bateria in Media with Tetracycline

Use this data to answer question 86-90.

86. When the two different E. coli strains, with and without the plasmid, were grown in nutrient media without antibiotic, which of the following occurred?

(A) The strain without the plasmid did not reach maximum growth potential.

(B) Both strains reached maximum growth potential.

(D) Neither strains reached maximum growth potential.

(E) The strain with the plasmid had a higher population density than the strain without the plasmid.

87. When the two strains cultured in nutrient media with the antibiotic tetracycline

(A) The strain without the plasmid was able to reach maximum population potential.

(B) Both strains reached maximum population potential

(D) Neither strain was able to reach maximum population potential

(E) Tetracycline did not affect either bacterial colony

88. The plasmid found in this E. coli strain codes for an enzyme that

(A) Allows e. coli to grow in the presence of tetracycline

(B) Digests the nutrient media

(D) makes this E. coli strain virulent

(E) None of the above

89. Which of the following would not be found in the plasmid?

(A) Thymine

(B) Adenine

(D) Cytosine

(E) Guanine

90. The E. coli strain with the plasmid

(A) Is more fit in regular media than the strain without the plasmid

(B) Is a result of genetic mutation

(D) Has a competitive advantage when grown in regular media

(E) Has a competitive advantage when grown in the media that contains tetracycline

91. Which statement about glycolysis is NOT ture?

(A) Glycolysisconverts a single molecule into two molecules of pyruvate.

(B) Glycolysis can produce a net total of 2 ATPs for each glucose.

(D) During glycolysis, FADH₂is produced.

(E) During glycolysis, NADH is produced

92. A cell is placed in a msdium containing radioactively labelled thymine. If the cell undergoes two rounds of replication while it this medium, some of the radioactivity will appear

(A) In each DNA double-helix

(B) In half of the strands of DNA

(D) In the mRNA

(E) In the tRNA

93. Which statement regarading protein synthesis is false?

(A) tRNA molecules help imcorporate the correct amino acids into proteins.

(B) Proteins are formed on the ribosomes.

(D) Ribosomal RNA is needed for proper binding of the mRNA message.

(E) Ribosomes are found either in the cytoplasm or attached to the enoplasmic reticulum.

94. Which of the following is an acceptable nitrogen base composition for double-stranded DNA?

(A) 31%A;19%T;31%C;19%G

(B) 36%A;36%U;24%C;24%G

(D) 31%A;31%T;19%C;19%G

(E) 24%A;24%U;36%C;36%G

95. The genetic code is considered degenerate because

(A) More than one codon can code for a single amino acid

(B) One codon can code for multiple amino acid

(D) Only one anticodon can bind to a given condon

(E) None of the above

In 1992, Alfred Hershey and Martha Chase conducted a set of experiments to determine whether DNA or proteins were the genetic material of living organisms. The original experiments took advantage of the fact that sulphur is not a component of DNA but is found in most proteins, while phosphorous is a component of DNA and not of proteins. Variations of the Hershey-Chase experiments have been performed by other researchers, as described below. These experiments used lambda bacteriophage has both a lytic cycle and a lysogenic cycle

Experiment 1:

The protein coat of lambda bacteriophage was labelled with radioactive sulphur,³⁵S. This phage culture was then allowed to infect a culture of E. coli. The phage carcasses, called ghosts, were separated from the bacterial cells were separated by centrifugation and the radioactivity was measured.

Experiment2:

The phage DNA was labelled with radioaction phosphorus,³²P. This phage culture was then allowed to enfact E. coli. The phage carasses, called ghosts, were separated from the bacterial cells befor any various could be produced. The bacterial cells were separated by centrifugation and the radioactivity was measured.

Use this information to answer question 96-99 below.

96. In Experiment 1, the radio-labeled sulphur subsequently appeared in.

(A) E. coli proteins

(B) E. coli chromosomes

(D) Lambda ghost DNA

(E) None of the above

97. In Experiment 2, most of the radioactivity was found in

(A) Lambda ghosts

(B) E. coli cells

(D) Lambda progeny

(E) None of the above

98. ³²P-labeled phage infected a culture of E. coli and entered a lysogenic cycle. The radioactivity of a 1 mL sample of the culture with a concentration of 1x105 cells/mL was measured. The E. coli were then allowed to undergo 3 rounds of replication. What fraction of the intitial to a final concentration of 1 l 105 cells/ mL, from the culture containing the final generation of E. coli?

(A) 1/8

(B) 1/4

(D) 1/3

(E) 1/2

99. After centrifugation of the E. coli using standard laboratory protocols, all of the following structures would be found EXCEPT

(A) Ribosomes

(B) DNA

(D) Cell walls

(E) RNA

In your town, people who drank water from a particular well developed a serious bacterial infection. In order to isolate the causative agent, you perform the following experiment.

You take a water sample from the well and inoculate a nutrient agar plate (Plate I) and a nutrient agar plate containing tetracycline, an antibiotic (Plate II). You also inoculate a nutrient agar plate with a sample you isolated from one your patients (Plate III). As a control, you inoculate a plate of nutrient agar with distilled water (Plate IV). The results are depicated as the figures below.

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100.Which of the following explains the growth pattern of plate1?

(A) Bacteria 2 produces an antibiotic to which bacteria 1,3 and 4 are susceptible.

(B) Bacteria 2 produces an antibiotic to which bacteria 4 is susceptible.

(D) Bacteria 4 requires a protein produced by bacteria1.

(E) Bacteria 4 requires a protein produced by bacteria 3.

Answer Key

1. E

2. A

3. E

4. E

5. E

6. B

7. D

8. C

9. D

10. B

11. E

12. D

13. B

14. C

15. A

16. D

17. B

18. B

19. E

20. B

21. C

22. C

23. D

24. A

25. C

26. E

27. C

28. E

29. C

30. C

31. D

32. C

33. E

34. D

35. A

36. D

37. C

38. D

39. B

40. B

41. A

42. D

43. D

44. C

45. B

46. D

47. B

48. C

49. D

50. A

51. B

52. B

53. R

54. D

55. A

56. B

57. B

58. D

59. D

60. B

Ecological Section

61. C

62. C

63. A

64. D

65. B

66. C

67. C

68. B

69. B

70. A

71. A

72. C

73. B

74. B

75. C

76. A

77. D

78. D

79. D

80. C

Molecular Section

81. B

82. B

83. E

84. E

85. B

86. B

87. C

88. A

89. C

90. E

91. D

92. A

93. C

94. D

95. A

96. C

97. B

98. A

99. C

100.B

ANSWER AND EXPLANATIONS

1. (E) All forms of life, from bacteria to man, have certain things in common. They all have some form of nucleic acid as genetic material as well as proteins, and they are composed largely of water.

2. (A) Clottingoccurs when platelets in an open wound release thromboplastin, which initiates a series of reactions ultimately leading to the formation of a fibrin clot. Thromboplastin, with the aid of calcium and vitamin K as cofactors, converts inactive plasma prothrombin to the active form thrombin in a series of steps. Thrombin in its turn converts fibrinogen (dissolved in plasma) into the fibrinous protein fibrin. Finally, threads of fibrin trap red blood cells to form clots.

3. (E) Pepsin, trypsin, carboxypeptidase, and chymotrypsin are all enzymes that digest proteins. Gastrin is a hormone released by the pyloric muclsa when food enters the stomach. It stimulates the secretion of gastric juices.

4. (E) The bony skeleton serves as a support system within many vertebrate organisms. Muscles are attached to the bones, permitting movement. The skeleton also provides protection for vital organs. For example, the rib cage protects the heart and the lungs, while the skull and vertebral column protect the brain and the spinal cord. The hollow cavity formed within many bones is filled with bone marrow the site of formation of blood cells.

5. (E) The endosymbiotic hypothesis proposes that primitive blue-green algae entered into a symbiotic arrangement with early eukaryotic cells to develop into chloroplasts, while a prokaryote ancestor entered into a similar arrangement with the precursors of eukaryotic cells to become mitochondria. Chloroplasts and mitochondria have circular DNA and genomes like modern prokaryotes. They have their own translation system as well. Thefact that they have lipid bilayer membranes does not necessarily support the hypothesis, since other organelles also are membrane bound with no evidence of endosymbiotic origin.

6. (B) if the electron transport chain is blocked in a cell that utilizes aerobic respiration to produce ATP them the amount of glucose consumed will increase. This is because the cell is only able to produce ATP through glycolysis.

7. (D) The large amount of air that come into the upper respiratory passages during panting permit water evaporation from the mucosal surfaces, therby allowing for heat loss. Panting is turned on by the thermoregulatory centers of the brain that monitor blood temperatures.

8. (C) As blood passes through the capillary fuft of the glomerulus, it is filtered as it passes through the capillary walls. Blood cells and protein remain in the blood, while water, salts, glucose, and amino acids are filtered into the Bowman’s capsule. Resorption of amino acids, glucose, and salts occurs predominantly in the proximal convoluted tubules. The cell lining the tubules actively transport these material out of the tubular lumen and into the peritubular capillary network. Movement of these materials produces an osmotic gradient that drives some water out of the tubules through simultaneous passive diffusion. In (D), villi are small projection in the walls of the small intestine that increase thesurface area to facilitate absoption of nutrients. As for (E), the ureter is a duct that carries urine from the kidney to the bladder.

9. (D) Cardiac cells have intercalated disk conections joining the cytoplasm between adjoining cardiac muscle cells. Although thay have some striations, they are not voluntary. Smooth muscle on the other hand, has striations, is mononuclear, and is involuntary. White blood cells lack nuclei, in order to make room for as much haemoglobin as possible.

10. (B) A cell that is n (haploid) cannot undergo meiosis to become 1/2n. (A) and (D) are incorrect, however, because haploid organisms undergo mitosis to grow. An example of such an organism is a braconid wasp. These animals in the haploid form are males (n); females (2n) are only formed when a female mates. As for (E), an organism, whether diploid or haploid, must be able to transcribe genes and make ATP to maintain life.

11. (E) This question illustrates two types of test cross. A test is performed to determine if a particular dominant individual’s phenotype is a homozygous or heterozygous genotype. In this case, there are two possible tall genotypes for the tall plant----TT, the pure homozygous tall, and Tt, the hybrid heterozygous tall. These two individuals would have the same phenotype. To determine the genotype, the unknown tall plant would be mated with a recessive, short plant. If the tall offspring, then it can be assumed that the original tall plant is homozygous TT. If the mating of the unknown tall organism and the short organism produces any short offspring at all, then we know that the original unknown tall was heterozygous. This is because short gamete is produced from each parent. In I, crossing an unknown with a Tt will also give you the information you seek, because if any short progeny are produced at all your unknown must be heterozygous, if all the offspring are tall your unknown must be homozygous dominant.

12. (D) The question is aksing you where growth occurs in long bone. The answer is in the epiphyseal plates. The epiphyseal plates are regions of the cartilaginous cells separating he shaft of the long bone, called the diaphysis, from its two dilated ends, called the epiphyses. The epiphyseal plates are located at either end of long bone, which are referred to as the proximal and distal ends. Since growth occurs only at the epiphyseal plates, the strontium would be incorporated near the plates.

13. (B) Blood leaving the kidneys travels through the inferior vena cava before entering the right atrium. All of the blood from the lower half of the body is collected in the inferior vena cava. This vessel merges with the superior vena cava ( which collects blood from the upper half of the body) immediately before it enters the right atrium. In (A), the iliacveins circulate blood in each leg and return it to the more central portions of the body before joining to become the common iliac vein, which then enters the inferior vena cava. As for (C) and (D), blood enters the liver through the hepatic portal artery after absorbing monosaccharides and amino acids from the small intestine. It leaves the liver through the hepatic portal vein after filtration occurs. Finally, in (E), the pulmonary vein brings blood back from the lungs to the left atrium. This blood has already reached the heart via the right atrium.

14. (C) The vitamin K we need for blood coagulation is synthesized by the intestinal bacteria residin in our colons. Vitamin K is required by the liver to synthesize some important blood factors. Deficiency of Vitamin K leads to defective blood clothing.

15. (A) Bicarbonate ions are secreted by the pancreas into the small intestine and acto to neutralize the acis of the stomach as it passes into the intestine. Bicarbonate ion is involved in transporting CO2 and to the lungs, but not O2 (C). Also, this does not occur in the digestive tract.

16. (D) Fermentation is a process that occurs during anaerobic respiration in organisms such as yeast. Glucose is converted to pyruvic acid, producing ATP. Then pyruvic acis is changed into ethyl alcohol, a waster plroduct of the fermentation process. Fermentation produces energy but does not require oxygen. The oxygen-requiring reactions of respiration occur in aerobic respiration, not in fermentation, and they occur in aerobic respiration, not in fermentation, and they occur as NADH and FADH2 molecules produced in the Krebs cycle are sent to the electron transport chain for the production of ATPs. The final electron acceptor in these reactions is oxygen. In fermentation, there is no aerobic stage, and ATP is never produced through a Krebs and electron transport chain mechanism.

17. (B) This question is a matter of knowing the pathway that blood travels in the heart. Deoxygenated blood drains into the right atrium from both the inferior vena cana and the superior vena cava. From the right atrium, the blood flows into the right ventricle, which then pumps it to the lungs via the pulmonary arteries. Carbon dioxide is exchanged for oxygen in the alveoli of the lungs. Oxygenated blood is returned to the left atrium via the pulmonary veins. From the left atrium, the blood drains into the left ventricle, which pumps it into the aorta for circulation throughout the body. Hence if a tracer substance is injected into the superior vena cana, it would take the longest amount of time to reach the left ventricle.

18. (B) The heart internally generates the rhythmic stimulation that triggers each heawrtbeat. The impulse for each heartbeat begins in the sinoatrial node, located in the wall of the right atrium at the approximate point at which the vena cava enters and travels through the atria. It is then picked up by the AV nodes and carried to the AV bundle (also known as the bundle of His) and transported through the ventricles through the Purkinje fibers. (A) and (C) are structures in the fetal heart that ensure that blood is shunted away from the fetus developing lungs. The vagus nerve (E) is a cranial nerve that regulates the heart beat in accordance with signals from the parasympathetic nervous system, although it does not determine the heartbeat. The SA node is able to maintain the heartbeat without any stimulation from the nervous system.

19. (E) insulin is the hormone secreted by the beta cells of the pancreas in response to high blood glucose levels. Insulin decreases blood glucose by stimulating cells to uptake glucose, and by stimulating the conversion of glucose into its storage form, glycogen, in the liver and muscle cells. An overdoes of insulin can, and often does, lead to a sharp decrease in blood glucose concentration.

20. (B) Identical twins are produced when a zygote formed by one egg and one sperm splits during the four or eight cell stage to develop into two genetically identical organisms. Identical twins (A) will always be of the same sex, but fraternal twins can also be of the same sex. The twins in (D) are termed fraternal twins and are not more genetically alike than siblings. (C) and (E), meanwhile, are impossible events.

21. (C) An amphioxus is a chordate but not a vertebrage. Chordates have a stiff dorsal rod called the notochord during a certain period of their embryological development, and emphiocus and tunicate worms do not lose their notochords, Chordates also have paired gill slits, a dorsal hollow nerve cord, and a tail extending beyong the anus at some point during development. Vertebrates , meanwhile, have bones called vertebrae that form the backbone. Bony vertebrae replace the notochord of the embryo and protect the nerve cord. Mammals, amphibians, reptiles, birds, and fish all ossess these vertebrae. Lets touch on the other choices here: the duckbilled platypus. (A) is an example of a reptile; the trout (D) is a fish, and rabbits (E) are mammals (all mammals are vertebrates).

22. (C) Acetylcholine is a neurotransmitter, which causes depolarization of the postsynaptic membrance of one neuron when rleased by the presynaptic terminal of another neuron. Acetylcholine is removed from the synapse by the enzyme acetyl cholinesterase. Anticholinesterase inhibitors like parathion disrupt this activity, meaning that the acetylcholine can’t be degraded and the concentration of acetylcholine in the synapse will increase.

23. (D) If a homozygous dominant, TTLL< is crossed with any genotype, the offspring will be heterozygous nd have the dominant phenotype. All the other options have potential for some homozygous recessives.

24. (A) Red blood cells are produced in the bone marrow. They lost their nuclei to make room fro more haemoglobin, which means that they cannot reproduce, repair themselves, or make plroteins. Red blood cells actually greatly outnumber leukocytes (white blood cells) (C); as for (D), the spleen stores a reservoir of red blood cells and acts as a biological and physical filter for the blood, but it does not make red blood cells.

25. (C) The notochord appears as a semirigid rod in the dorsal part of all chordates sometime during embryonic development. In lower chordates, this remains as a semirigid chord, although in higher chordates it is seen only in the embryo and not as a vestigial organ. Echinoderms (B) do not possess a notochord. As for (C), the notochord remains in the lower chordates, such as the amphioxus and the tunicate worm, while the notochord (E) is not part of the nervous system.

26. (E) During meiosis, the gamete reduces its genetic component from 2n to n, resulting in a haploid cell with half the normal chromosome number. When a haploid egg and sperm unite, they form a diploid organism known as a zygote. All ova will diploid organism known as a zygote. All ova will contain an X chromosome and all splerm will contain either an X or Y chromosome. These gametes are formed during the two reductional divisions called meiosis. During metaphase I of meiosis I, tetrads form, and sister chromatids undergo the homologous recombination known as crossing over.

27. Alveoli are thin air sacs that act as the sites of air exchange between the environment and the blood via passive diffusion. The bronchi (E) are the two main branches of the air intake pathway. One bronchus goes to each lung, and each bronchus is divided into smaller sections termed bronchioles. The trachea (D) is the region of the air intake pathway located between the glottis and the bronchi. It is also known as the windpipe.

28. (E) Pheromones like primes or releaser pheromones are substance secreted by organism that alter the behaviour of other members of that organism’s species.

29. (C) The breathing center in the medulla oblongata monitors the increase in CO₂ through its sensory cells,. It will also detect a decrease in pH in the blood, which is indicative of an increase of CO₂ levels in the blood. A decrease in O₂ is monitored peripherally by chemoreceptors, located in the carotid bodies in the carotid arteries and in the aortic bodies in the aorta. In (A), the cerebrum is involved in sensory interpretation, mamory and thought, while the cerebellum (B) is involved in fine motor coordination balance and equilibrium. Finally, the spinal cord (D) relays sensory and motor information to and from the brain, and the hypothalamus (E) regulates hunger thirst, body temperature, sex drive, and emotion.

30. (C) Enzymes are catalysts of biological reaction, increasing the rate of reactions without them-selves changing and without changing the final equilibrium. Enzymes are typically proteins (I), although they may rarely be RNA, and they typically act most effectively at a physiological pH of 7-7.4 (except for the enzyme which break down protein in the stomach, which act most effectively in an acidic environment) (II). Enzymes are never changed during a reaction (III). They increase the rate of a reaction, but are not themselves the rate of a reaction. Enzymes are found throughout the cell, not just in the nucleus (IV).

31. (D) In the nucleus, DNA is produced during cell division, while RNA is produced by transcription of DNA. mRNA travels from the nucleus into the cytoplasm, where it is translated into polypepetides on the ribosomes.

32. (C) The plasma membrance separates the cellular contents from the environment. It is responsible for the permeability of the membrane---in other words, for what is allowed in amd out of the cell. The fluid mosalic model of the plasma membrane states that this membrabe is a bilayer of phospholipid interspersed with protein acting as receptors, pores, and channels. The pores and channels cross the entire membrane. The cytochrome chain referred to inthe correct answer is actually located in the cristae ( the inner membrane ) of the mitochondria.

33. (E) A point mutation change the sequence of one nucleotide; a silent mutation (B), on the other hand, affects the DNA sequence, but does not affect the protein produced from that DNA is altered and the protein produced is rendered non-functional.

34. (D) As an exocrine gland, the pancreas secretes proteases, lipases, and amylases that aid in the digestion of food, as well as bicarbonate ion that buffers the pH of the chime coming from the stomach. Glucagon, meanwhile, is an endocrine gland secreted by the pancreas in response to a low blood glucose level. It causes an increase in the levels of glucose by degrading glycogen and decreasing the uptake of glucose by muscles.

35. (A) The phloem, the thin-walled cells on the outside of the vascular bondle, transports nutrients down the stem of the plant.

36. (D) the xylem, the thick-walled, usually hollow cells on the inside of the vascular bundles, transports water and minerals up the plant stem.

37. (C) The cambium is two cells thick and located in between the xylem and phloem. These actively dividing, undifferentiated cells give rise to the xylem and the phloem.

38. (D) The pith is the innermost tissue layer that is used for the storage of nutrients and plant support.

39. (B) Bacteria contain extrachromosoomal circular DNA called plasmids. They often code for genes that code for antibiotic resistance or other things that increase the fitness of the bacteria.

40. (B) Bacteria are prokaryotes. These organisms have a plasma membrane, and lack membrane-bound organelles and a true nucleus.

41. (A) Viruses are composed of genetic material, either DNA or RNA, enclosed in a protein coat called a capsid. They are obligate parasites in that they cannot replicate unless they have infected a host cell.

42. (D) Planaria are bilaterally symmetrical, with two sides that are mirror images of each other.

43. (D) The electron transport chain uses a proton pump to drive the ATP synthase that produces ATP. It is found in the inner mitochondrial membrane of the mitochondria. The energy of the protein gradient is harvested by the cell through the production of large quantities of ATP.

44. (C) The Krebs cycle occurs in the mitochondrial matrix.

45. (B) Fermentation is anaerobic and regenerates NAD⁺ for glycolysis.

46. (D) See the explanation to question 43.

47. (B) The byproducts of fermentation are ethanol ( in prokaryotes and some yeast) and lactic acid ( in most of the other eukaryotes, including humans). The buildup of lactic acid accounts for the soreness of your muscles after a tough workout.

48. (C) The function of a circulatory system is to transport gases, mutrients, and wastes throughout the body.

49. (D) The nervous system receives input from the five senses. This input is analyzed by the central nervous system and acted upon by the motor neurons. This allows organisms to receive and respond to stimuli.

50. (A) The musculoskeletal system forms the basic framework for the human body. Everythings alse is either built upon this framework or protected within it.

51. (B) The hormones secreted by the various endocrine organs allow tissues and organs to communicate. This is crucial for the maintenance of homeostasis, reproduction, and other life functions.

52. (B) Guanine ( along with adenine) is a purine that binds cytosine (a pyrimidine) via three hydrogen bonds.

53. (E) Uracil is a pyrimidine found only in RNA.

54. (D) See the explanation for question 52.

55. (A) Adenine (along with guanine) is a purine that binds thymine with two hydrogen bonds in DNA and uracil with two hydrogen bonds in RNA.

56. (B) In order for Hardy-Weinberg equilibrium to be maintained, a large population no net mutrtions, no migration, and random mating must all occur. If these criteria are met, then the allele frequencies for two allele must equal 1, p + q = 1. The phenotypic frequencies must also equal one in the following equation p² + 2pq + q² = 1. In this case, T = 0.8, so p = 0.8 0.8 +q=1, so q =0.2. therefore, the allele frequency of t is 20 percent, or 0.2.

57. (B) The percentage of heterozygous individuals is defined by the 2pq term. So, 2(0.8)(0.2) = the percentage of heterozygous individuals, which comes to 0.32 or 32 percent.

58. (D) Individuals that can curl their tongues have at least one dominant allele. This means that you are looking for the number of p² individuals , who have two dominant allele and the number of 2pq individuals, who have only one dominant allele. These two numbers added together will give you the number of individuals that can curl their tongues. Therefore, (0.8)2 + 2(0.8)(0.2) = 0.96 or 96 percent.

59. (D) The bacteria that have the largest population are growing most optimally. In this experiment, the optimum concentration is at 40 U/mL.

60. (B) The second time the mouse tried the maze he cut his time in half, from 40 to 20 seconds or a 50 percent increase. The next largest drop in time is after the third trial, when the mouse shaved 9 seconds off his previous time.

Ecological Section

61. (C) Station B has low annual precipitation, so it cannot be located in choice (B) rainforest. Its elevation is high, which eliminates (E) estuary as a possibility. Station B’s average minimum and maximum temperatures are both well above freezing, so it is unlikely to be either (D) tundra or (A) taiga. The only remaining choice is (C) desert.

62. (C) Coniferous forests are characteristic of taiga, a moderately dry, cool, high latitudebiome. Stations A and B are extremely dry, as their low annual precipitation totals indicate. Station D and E are both warm and wet. The only remaining choice is (C).

63. (A) Production in a given biome is heavily influenced by temperature and rainful. The station with the most adverse conditions (cold and dry ) is A. All of the others (B,C,D and E) have higher mean temperatures or precipitation totals, or both.

64. (D) Lake are partially fed by groundwater. Station D is nearly at see level, which makes it most likely to be on a coast, the interface between salty seawater and fresh groundwater. As groundwater is removed for human use, salt water may be drawn in to replace the fresh. Saltwater sinks the lower layers saltier and less hospitable to the bottom-dwelling clams.

65. (B) Environmental resistance is the sum of all the factors that limit a population’s growth, including predators (A) food supply (C) weather (D) and competition for space (E). reproductive success is an element of biotic potential, a population’s capacity for growth if no limiting factors are considered.it does not contribute to environemetal resistance, it is an opposing force and biotic potential are in equilibrium.

66. (C) Although increased plant growth due to excessive nutrient levels is characteristic of eutrophic lakes, it actually creates an imbalance by stimulating photosynthesis.

67. (C) Phosphate is returned to its nutrient (inorganic) state by decomposers, which are prominent in the processes described in choice I and II. At their present life stage, the moss and larger plants it supports are removing more phosphate from the soil than is being returned.

68. (B) Gypsy moths did not evolve to suit their present environment. They just happened to be able to take advantage of the resources it offered. Choices (A),(C), (D), and (E) are some of the typical keys to the success of non-native species.

69. )B( The first few species to inhabit a newly disturbed area are called pioneer species the dandelions fit this description. Dandelions are not a keystone species, as their work in the ecosystem ( breaking down ash into etc,) could be performed as well by some other pioneer species. Dandelions produce many offspring with little parental investment, and disperse them widely; thus they are an example of an r-strategist organism.

70. (A) All of the choices plausible except (A), because the size of a dandelion population is controlled mostly by density in depend factors, end they have evolved to maximize population growth rate. Therefore, they are not as limited by carrying capacity as are slower-reproducing, more density dependent, species.

71. (A) Energy is only conserved in a closed system an ecosystem is not closed. At every step in the food chain, some energy is lost as heat, which cannot be captured and used by another organism. Solar energy captured in photosynthesis is stored in plants, the basis of most food chains. ( Note on choice (B):Recently explored ecosystems, such as those near hydrothermal vents on the ocean floor are driven by energy derived from chemosynthesis, which requires no solar energy.)

72. (C) Each of the answers describes a type of symbiotic relationship. Both the crab and the anemone benefit from living together, a condition known as mutualism. A parasite does harm to its host, as a predator does harm to its prey. Commensalism describes an association in which one organism benefits and the other neither benefits nor is harmed by the first. In competition, both organisms are harmed because resources must be divided between them.

73. (B) Unlike energy nutrients are recycled through the ecosystem, to be used again and again. Decomposers transform nutrients from an unusable from (waste) to the form in which they are able to reenter the cycle through plants, choice (C); parasites live off live organisms, while decomposers live off dead matter. Choice (D). Decomposers aredependent on autotrophs, as they cannot produce their own food from non-living resources. Choice (E). the original statement is correct.

74. (B) Oak trees are autotrophs (producers), squirrels eat acorns and thus primary consumers, foxes eat squirrels (secondary consumers), and blowflies lay eggs in carrion and thus are decomposers.

75. (C) Jewel beetles migrate to sites of recent forest fires, which may be randomly distributed in the landscape. However, the beetles will form a population whose range is limited to the burn site. This results in a clumped dispersal pattern.

76. (A) Since rodents are selective eaters, low densities allow them to graze only on their preferred plants, allowing less desirable species to dominate the ecosystem. Greater density forces rodents to choose a wider range of plants, preventing any one species from predominating and leading to greater diversity overall. At very high rodent densities, competition for all food species will result in some species being 100% consumed, reducing plant diversity.

77. (D) A large raptor population would reduce rodent density. According to the graph, low rodent density is associated with low food-species diversity.

78. (D) The number and variety of plants in an ecosystem is density-dependent. Since the plants are the prey of the rodents both populations are density-dependent. These two groups do not compete for a niche, so niche differentiation is not necessary.

79. (D) The pyramid is top-heavy indicating a greater proportion of older members in the population. The number of younger members is not sufficient either to replaced the older members one-for-one (a stable dietribution), or to replace them by a higher ratio (a growing population). Natality refers only to the rate at which new individuals are born; the rate at which those offspring survive is what really makes the difference to a population as a whole.

80. (C) Although nitrogen is many times more abundant in air than carbon dioxide, both nutrients are sufficiently abundant to satisfy the needs of primary producers. Unlike CO₂ however N₂ must be “fixed” as nitrate by certain bacteria before it is in a form usable to most autotrophs.

Molecular Section

81. ( B) Hexokiness, like all enzymes, reduces the activation energy of a reaction to makes it go faster, but it does not change the end point, the equilibrium, of the reaction. Enzymes are not consumed in a reaction (D) and catalyze both the forward and the reverse reaction (E).

82. (B) In the graph the reaction rate increases linearly with increasing enzyme. Doubling the amount of enzyme will double the rate of the reaction. ADP is one of the products of the reaction, along with glucose 6-phosphate, so its production will double with twice the enzyme present.

83. (E) Enzymes catalyze reactions at a specific active site in the protein structure. As more substrate is added ( glucose) the active sites become full, or saturated. In the graph, the reaction rate increases as more glucose is added at first, then levels off. The graph indicates that there is no increase in the reaction rate above 3 uM glucose, because the active sites of the enzyme are full. If the reaction is saturated, then adding more glucose will not change either glucose 6-phosphate production or ATP consumption.

84. (E) DNA replication is semiconservative in that the two daughter double helices each receive one strand from the parent DNA. DNA replication occurs at Interphase, but only in a 5’ to 3’ direction not 3’ to 5’. This forms Okasaki fragments on the leading strand. Purines (such as adenine and gusnine) always bind with pyrimidines (like thymine and cytosine).

85. (B) In glycolusis and the Krebs cycle, energy is extracted from glucose and transferred to NADH and FADH. Iin electron transport the energy of NADH and FADH₂ is transferred to a series of proteins in the inner mitochondrial membrane, with as the final electron acceptor at the end of the chain² .this electron transport chain pumps protons out of the mitochondria creating a proton gradient. The energy of the gradient drives the ATP synthesis. Each NADH leads to three ATP and each FADH₂creates two. Without ₂ there is no electron transport or oxidative phosphorylation.

86. (B) Without antibiotics, both strains reached their maximum growth potential.

87. (C) With the antibiotics in Graph 2, only the E. coli strain that has the plasmid reached its maximum growth potential. The strain that did not have the plasmid could not grow.

88. (A) The plasmid must allow the bacteria to grow in the presence of an antibacterial compound such as tetracycline, probably by activating the antibiotic or giving the bacteria a way to get around the inhibition of the antibiotic.

89. (C) Plasmids are circular pieces of extra chromosomal DNA, and uracil is a component of RNA not found in DNA.

90. (E) Natural selection state that fitter organisms have a competitive advantage over unfit organisms where fitness is defined by the ability to reproduce. Therefore a bacteria that can grow in the presence of an antibiotic such as tetracycline is more fit and has a competitive advantage over a strain that does not presence of tetracycline.

91. (D) The first set of reactions are anaerobic and involve the breakdown of glucose into pyruvate (A). Two ATP molecules are required and four are produced, leaving a net total of 2 ATP/ glucose (B). Pyruvic acid will either become acetyl CoA and enter the Krebs cycle during aerobic respiration or will become lactic acid or ethanol in anaerobic respiration (C). Two NADH molecules are produced by glycolysis; these will donate their electrons to compound Q in the electron transport chain (E). FADH₂ however is not produced until the Krebs cycle.

92. (A) DNA replication is semiconservative. In consequence after the DNA has been replicated in the medium containing a radioactive tracer every helix of DNA will have at least one strand that will have incorporated some of the radioactivity . after two rounds of DNA replication, there will be four copies of DNA, two that have the radioactive tracer in both strands and two that have the tracer in only one of the dtrands.

93. (C) Protein synthesis does require mRNA. tRNA (A)brings the amino acid to the ribosome, where it interacts with the mRNA that has the appropriate sequence. As for (B), tRNAmolecules do in fact have an amino acid bound to their 3’ end. The mRNA is read from 5’ to 3’ as the ribosome moves along the message. (D) and (E) are also both true.

94. (D) Because DNA is double stranded and because of the rules of complementary base pairing, the quantity of adenine must equal the quantity of thymine, and the quantity of cytosine mu st equal the quantity of guanine. The reason for this is that in DNA, adenine will bind only with thymine, while cytosine binds only with guanine. After eliminating the answer choices that do not follow this rule, you can eliminate any answer choices that mention uracil since it is found only in RNA. Finaly to reach the correct answer, you must add up your percentsges and make sure that they equal 100 percent of the bases in the DNA strand.

95. (A) The genetic code is referred to as “degenerate” because more than one codon can code for each of an amino acid. For example, both UAU and UAC code for tyrosine. Since there are three bases in a codon, there are 64 possible codon and only 20 amino acids.(B) is the opposite of answer choice (A) and therefore untrue. It is essential that the anticodon be the exact base pair complement of the codon to maintain protein integrity. (D) is true, but it does not account for the degeneracy of the genetic code.

96. (C) When the ³²P labelled phage were used in Experiment 2, most of the radioactivity ended up inside the bacterialcells, indicating that the phage DNA entered the cells. If the phage had been allowed to enter a lytic cycle, the ³²P would also have been recovered in the phage progeny. In Experiment 1, when the ³⁵S-labeled phage were used most of the radioactive material ended up iin the phage ghosts, indicated that the phage protein never entered the bacterialcell. The conelusion to be drawn from these experiments is that DNA is the hereditary material, and that phage protein are mere structural packaging that is discarded after delivering the viral DNA to the bacterial cell. The entire “life purpose” of a virus is devoted to finding a host cell and getting its nucleic acid inside it. This is crucial for a virus since it must use the genetic machinery of a host cell to replicate. Since the protein was labelled with ³⁵S you would expect to find this isotope of sulphur only in the viral ghost, which you’re told is the phage carcass. And since the DNA was labelled with ³²P you would expect to find this radioactive isolope only in the bacterial cells.

97. (B) See the explanation 76 above.

98. (A) We know that the radio-labeled phage DNA has been inserted into the bacterial chromosome and will undergo replication just as if it were native bacterial DNA. During DNA replication the double helix unwinds and each strand acts as a template for complementary base-pairing in the synthesis of two new daughter helices. Each new daughter helix, which in this problem contains radioactivity and a newly synthesized strand, which contains no radioactivity, since all of its nucleotides were synthesized by the bacterial cell. Thus DNA replication is semiconservative ---half of the original DNA is conserved from one generation to the next. Since every bacterial cell division doubles the number of cells and the total amount of DNA, three round of replication will increase the total number of cells and the total amount of DNA by a factor of eight while the amount of radioactivity remains constant. In essence, the ³²p is diluted with each round of replication. This means that the fraction of radioactivity in a 1 mL sample taken from the culture of the final generation will be one-eighth the amount of radioactivity taken from a culture of the parental generation, after the cultures are diluted to have the same number of cell/mL.

99. (C) This question tests your ability to differentiate between prokaryotic and eukaryotic cells. A prokaryote is a unicellular organism that lacks membrane-bound organelles. Mitochondria, which are membrane bound, would not be found in a prokaryotic cell.

100.(B) Bacteria 4 grows all over the nutrient plate except in the regions surrounding Bacteria 2. The logical conclusion is that Bacteria 2 produces an antibiotic that kills Bacteria 4 (B). We don’t know whether or not this antibiotic can also kill Bacteria 1 and 3, since they are not in close enough proximity to Bacteria 2 to be affected by it.

8th DIAGNOSTIC TEST

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