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Unformatted text preview: AP® Biology 2009 Free-Response Questions The College Board
The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded in 1900, the association is composed of more than 5,600 schools, colleges, universities and other educational organizations. Each year, the College Board serves seven million students and their parents, 23,000 high schools and 3,800 colleges through major programs and services in college readiness, college admissions, guidance, assessment, financial aid, enrollment, and teaching and learning. Among its best-known programs are the SAT®, the PSAT/NMSQT® and the Advanced ® ® Placement Program (AP ). The College Board is committed to the principles of excellence and equity, and that commitment is embodied in all of its programs, services, activities and concerns. © 2009 The College Board. All rights reserved. College Board, Advanced Placement Program, AP, AP Central, SAT, and the acorn logo are registered trademarks of the College Board. PSAT/NMSQT is a registered trademark of the College Board and National Merit Scholarship Corporation. Permission to use copyrighted College Board materials may be requested online at: www.collegeboard.com/inquiry/cbpermit.html. Visit the College Board on the Web: www.collegeboard.com. AP Central is the official online home for the AP Program: apcentral.collegeboard.com. 2009 AP® BIOLOGY FREE-RESPONSE QUESTIONS BIOLOGY
SECTION II Time— 1 hour and 30 minutes Directions: Answer all questions. Answers must be in essay form. Outline form is not acceptable. Labeled diagrams may be used to supplement discussion, but in no case will a diagram alone suffice. It is important that you read each question completely before you begin to write. Write all your answers on the pages following the questions in the pink booklet. 1. An experiment on a species of small freshwater fish recorded their behavioral responses to different temperatures. Ten fish were each tested once, one at a time. To begin the experiment, a fish was removed from a stock tank (maintained at 22∞C ) and placed in the temperature-gradient tank drawn below. After the fish had spent 30 minutes in the temperature-gradient tank, the section where the fish was located was recorded. Additional observations were recorded every 5 minutes, for a total of 7 observations per fish. A summary of the combined data for all 10 fish appears below. (a) On the axes provided, construct the appropriate type of labeled graph showing the relationship between water temperature and fish distribution. Summarize the outcome of the experiment. (b) Identify TWO variables that were not specifically controlled in the experimental design, and describe how these variables might have affected the outcome of the experiment. (c) Discuss TWO ways that water temperature could affect the physiology of the fish in this experiment. Section Fish/Section A B C D E 9 11 34 12 4 © 2009 The College Board. All rights reserved. Visit the College Board on the Web: www.collegeboard.com. GO ON TO THE NEXT PAGE. -2- 2009 AP® BIOLOGY FREE-RESPONSE QUESTIONS
2. ATP and GTP are primary sources of energy for biochemical reactions. (a) Describe the structure of the ATP or the GTP molecule. (b) Explain how chemiosmosis produces ATP. (c) Describe TWO specific cell processes that require ATP and explain how ATP is used in each process. (d) An energy pyramid for a marine ecosystem is shown below. Label each trophic level of the pyramid and provide an example of a marine organism found at each level of this pyramid. Explain why the energy available at the top layer of the pyramid is a small percentage of the energy present at the bottom of the pyramid. 3. Phylogeny is the evolutionary history of a species. (a) The evolution of a species is dependent on changes in the genome of the species. Identify TWO mechanisms of genetic change, and explain how each affects genetic variation. (b) Based on the data in the table below, draw a phylogenetic tree that reflects the evolutionary relationships of the organisms based on the differences in their cytochrome c amino-acid sequences and explain the relationships of the organisms. Based on the data, identify which organism is most closely related to the chicken and explain your choice. (c) Describe TWO types of evidence— other than the comparison of proteins—that can be used to determine the phylogeny of organisms. Discuss one strength of each type of evidence you described. THE NUMBER OF AMINO ACID DIFFERENCES IN CYTOCHROME c AMONG VARIOUS ORGANISMS Horse Horse Donkey Chicken Penguin Snake 0 Donkey 1 0 Chicken 11 10 0 Penguin 13 12 3 0 Snake 21 20 18 17 0 © 2009 The College Board. All rights reserved. Visit the College Board on the Web: www.collegeboard.com. GO ON TO THE NEXT PAGE. -3- 2009 AP® BIOLOGY FREE-RESPONSE QUESTIONS
4. The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of biology. (a) Explain the role of each of the following in protein synthesis in eukaryotic cells. • • • • • RNA polymerase Spliceosomes (snRNPs) Codons Ribosomes tRNA (b) Cells regulate both protein synthesis and protein activity. Discuss TWO specific mechanisms of protein regulation in eukaryotic cells. (c) The central dogma does not apply to some viruses. Select a specific virus or type of virus and explain how it deviates from the central dogma. END OF EXAM © 2009 The College Board. All rights reserved. Visit the College Board on the Web: www.collegeboard.com. -4- ...
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