2002 AP® BIOLOGY FREE-RESPONSE QUESTIONS (Form B)

Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board.

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2. In mammals, heart rate during periods of exercise is linked to the intensity of exercise.

(a) Discuss the interactions of the respiratory, circulatory, and nervous systems during exercise.

(b) Design a controlled experiment to determine the relationship between intensity of exercise and heart rate.

(c) On the axes provided below, indicate results you expect for both the control and the experimental groups for the controlled experiment you described in part B. Remember to label the axes.

3. The physical form of cells and organisms is often influenced by special structural polymers. Choose one

polymer from each of the following three pairs of polymers:

Pair 1: tubulin . . myosin Pair 2: cellulose . . chitin Pair 3: messenger RNA . . transfer RNA For each of the three polymers you have chosen, describe its

(a) structure, and

(b) role in a cell or organism.

4. A triploblastic animal is one in which three germ layers form during embryonic development. Triploblastic

animals include acoelomate, pseudocoelomate, and coelomate (eucoelomate) organisms.

(a) Identify the three germ layers of a triploblastic embryo and discuss the fates of these germ layers in embryonic development.

(b) Describe acoelomate, pseudocoelomate, and coelomate body plans. Identify an animal that is represen-tative of each of these types of body plan.

(c) Compare and contrast the digestive systems of an acoelomate and a coelomate organism.

END OF EXAMINATION

AP® BIOLOGY 2002 SCORING GUIDELINES (Form B)

Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board.

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Question 3

6 points maximum for part (a) and part (b) below For each of the three polymers chosen, describe its:

(a) structure, and (6 points maximum)

(b) role in a cell or organism (6 points maximum) In the following tables, structural characteristics are listed first (2 points maximum)

then a row of asterisks * * * * * * * * * * * * * * * * * * *

and finally, roles (2 points maximum) are listed under the row of asterisks.

AP® BIOLOGY 2002 SCORING GUIDELINES (Form B)

Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board.

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Question 3 (cont’d.)

rol

e

s

truc

ture

m

ax. 2

poi

nts

m

ax. 2

poi

nts Tubulin

protein (amino acid) polymer α and β forms forms hollow tubes

************************ component of microtubules maintain cell shape (cytoskeleton) compose cilia and flagella help in chromosome migration/organelle movement

Myosin protein (amino acid) polymer has actin-binding sites (crossbridges) has ATP-binding site (crossbridges)

**************************** hydrolysis of ATP “flexes” actin-bound myosin crossbridges cause “sliding filament motion”

rol

e

s

truc

ture

m

ax. 2

poi

nts

max

. 2 p

oint

s

Cellulose carbohydrate/polysaccharide (glucose polymer) β-glucose form special β-glycosidic linkages straight, unbranched molecule (rigid) often bond in parallel bundles = microfibrils (fibers) water-insoluble

************************** plant cell wall component digestible for some microbes indigestible for others shape/firmness/stability

Chitin N-containing carbohydrate/polysaccharide (N-acetylglucosamine polymer) water-insoluble

**************************** fungal cell wall component arthropod exoskeleton material

role

st

ruct

ure

max

. 2 p

oint

s

m

ax. 2

poi

nts

Messenger RNA nucleic acid (nucleotide polymer) sugar/phosphate backbone with bases in center A, C, G, U nitrogen bases compliment of DNA section 5’ � 3’ orientation cap and/or polyA tail introns/exons (post-transcriptional modification) single-stranded

*************************** carries genetic message from DNA to ribosome/ exits nucleus template upon which protein is formed at ribosome gene regulation

Transfer RNA nucleic acid (nucleotide polymer) sugar/phosphate backbone with bases in center A, C, G, U nitrogen bases amino acid binding site anticodon triplet 3’ � 5’ orientation single-stranded except 4 base-paired regions (clover-leaf shape)

****************************** transfers amino acids from cytoplasm to ribosome allows attachment of amino acids onto peptide chain

AP® BIOLOGY 2002 SCORING COMMENTARY (Form B)

Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board.

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Question 3

Sample R (Score 10) A point was earned for tubulin for the structure being a protein and another for the alpha and beta forms. A third point was earned for the function of tubulin in microtubules, and an additional point was earned for the role of these in mitosis.

A point was earned for cellulose for a polymer of beta glucose and another for the straight, unbranched, structure. An additional point was earned for the structural component of the cell wall.

For mRNA, a point was earned for nitrogen base composition and another for being composed of nucleotides. The final point was earned for attachment of the ribosomes to translate the genetic information. Sample S (Score 8) A point was earned for tubulin for the protein nature of the molecule and another for the structure of the microtubule. A further point was earned for the description of the role of microtubules in helping to move organelles around the cell.

A point was earned for cellulose for the carbohydrate nature of the molecule and another for the component of the cell wall.

For mRNA, a point was earned for sugar-phosphate-base composition and a point for the 5’ to 3’ orientation. The final point was earned for discussing post-transcriptional processing. Sample T (Score 6) A point was earned for tubulin for the protein nature and a point for the structural component of microtubules. A third point was earned for the role of microtubules in the movement of organelles.

A point was earned for chitin for being a component of arthropod “armor.” For mRNA, a point was earned for the nucleotide composition of the molecule and another for the nitrogen

bases. The remaining lengthy discussion did not earn additional points.