Practice book biology


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Practice book biology

  1. 1. G R A D U A T E R E C O R D E X A M I N A T I O N S®Biology TestPractice BookThis practice book containsⅢ one actual, full-length GRE® Biology TestⅢ test-taking strategiesBecome familiar withⅢ test structure and contentⅢ test instructions and answering proceduresCompare your practice test results with the performance of those whotook the test at a GRE administration.This book is provided FREE with test registration by the Graduate Record Examinations Board.
  2. 2. Note to Test Takers: Keep this practice book until you receive your score report. This book contains important information about scoring. Copyright © 2008 by Educational Testing Service. All rights reserved. ETS, the ETS logos, LISTENING. LEARNING. LEADING., GRADUATE RECORD EXAMINATIONS,® and GRE are registered trademarks of Educational Testing Service (ETS) in the United States of America and other countries throughout the world.
  3. 3. The GRE Board recommends that scores on the Table of Contents Subject Tests be considered in conjunction with other relevant information about applicants. Because Purpose of the GRE Subject Tests ................... 3 numerous factors influence success in graduate Development of the Subject Tests ................... 3 school, reliance on a single measure to predict success is not advisable. Other indicators of compe- Content of the Biology Test ............................ 4 tence typically include undergraduate transcripts Preparing for a Subject Test ............................. 8 showing courses taken and grades earned, letters of Test-Taking Strategies ...................................... 8 recommendation, and GRE General Test scores. For information about the appropriate use of GRE What Your Scores Mean .................................. 9 scores, see the GRE Guide to the Use of Scores at Practice Biology Test....................................... 13 Scoring Your Subject Test ............................... 65 Evaluating Your Performance ......................... 68 Development of the Answer Sheet .................................................. 69 Subject Tests Each new edition of a Subject Test is developed by a committee of examiners composed of professors inPurpose of the GRE the subject who are on undergraduate and graduateSubject Tests faculties in different types of institutions and in different regions of the United States and Canada.The GRE Subject Tests are designed to help gradu- In selecting members for each committee, the GREate school admission committees and fellowship Program seeks the advice of appropriate professionalsponsors assess the qualifications of applicants in associations in the subject.specific fields of study. The tests also provide you The content and scope of each test are specifiedwith an assessment of your own qualifications. and reviewed periodically by the committee of Scores on the tests are intended to indicate examiners. Test questions are written by committeeknowledge of the subject matter emphasized in members and by other university faculty membersmany undergraduate programs as preparation for who are subject-matter specialists. All questionsgraduate study. Because past achievement is usually proposed for the test are reviewed and revised bya good indicator of future performance, the scores the committee and subject-matter specialists atare helpful in predicting success in graduate study. ETS. The tests are assembled in accordance withBecause the tests are standardized, the test scores the content specifications developed by the com-permit comparison of students from different mittee to ensure adequate coverage of the variousinstitutions with different undergraduate programs. aspects of the field and, at the same time, to preventFor some Subject Tests, subscores are provided in overemphasis on any single topic. The entire testaddition to the total score; these subscores indicate is then reviewed and approved by the committee.the strengths and weaknesses of your preparation,and they may help you plan future studies. BIOLOGY TEST 3 PRACTICE BOOK
  4. 4. Subject-matter and measurement specialists The maximum possible range for all Subject Teston the ETS staff assist the committee, providing total scores is from 200 to 990. The actual rangeinformation and advice about methods of test con- of scores for a particular Subject Test, however,struction and helping to prepare the questions and may be smaller. For Subject Tests that report sub-assemble the test. In addition, each test question is scores, the maximum possible range is 20 to 99;reviewed to eliminate language, symbols, or content however, the actual range of subscores for anyconsidered potentially offensive, inappropriate for test or test edition may be smaller than 20 to 99.major subgroups of the test-taking population, or Subject Test score interpretive information islikely to perpetuate any negative attitude that may be provided in Interpreting Your GRE Scores, whichconveyed to these subgroups. you will receive with your GRE score report. This Because of the diversity of undergraduate cur- publication is also available at, it is not possible for a single test to cover allthe material you may have studied. The examiners, Content of the Biology Testtherefore, select questions that test the basic knowl-edge and skills most important for successful graduate The GRE Biology examination is designed to evaluatestudy in the particular field. The committee keeps the the following abilities and background of the student.test up-to-date by regularly developing new editions Ⅲ Knowledge of basic vocabulary and facts inand revising existing editions. In this way, the test several biological fields at the equivalent ofcontent remains current. In addition, curriculum an upper-level course.surveys are conducted periodically to ensure thatthe content of a test reflects what is currently being Ⅲ Conceptual understanding of ideas, relation-taught in the undergraduate curriculum. ships, and processes After a new edition of a Subject Test is first Ⅲ Understanding of basic scientific research,administered, examinees’ responses to each test procedures, and toolsquestion are analyzed in a variety of ways to deter- Ⅲ Capacity to read, evaluate, and draw conclusionsmine whether each question functioned as expected. from unfamiliar laboratory and field studiesThese analyses may reveal that a question is ambigu-ous, requires knowledge beyond the scope of the test, Ⅲ Understanding of the connections amongor is inappropriate for the total group or a particular biological fields and between biological fieldssubgroup of examinees taking the test. Such questions and allied sciencesare not used in computing scores. The test contains about 200 five-choice questions, Following this analysis, the new test edition is a number of which are grouped in sets toward theequated to an existing test edition. In the equating end of the test and are based on descriptions ofprocess, statistical methods are used to assess the laboratory and field situations, diagrams, or experi-difficulty of the new test. Then scores are adjusted so mental results.that examinees who took a more difficult edition of To cover the broad field of the biological sciences,the test are not penalized, and examinees who took the subject matter on which the students are testedan easier edition of the test do not have an advantage. is organized into three major areas: cellular andVariations in the number of questions in the differ- molecular biology; organismal biology; and ecologyent editions of the test are also taken into account and evolution. Approximately equal weight is givenin this process. to each of these three areas. In addition to the total Scores on the Subject Tests are reported as three- score, a subscore in each of these subareas is reported.digit scaled scores with the third digit always zero.4 BIOLOGY TEST PRACTICE BOOK
  5. 5. The approximate distribution of questions by 6. Cytoskeleton, motility, and shapecontent category is shown below. However, subject Actin-based systemsareas indicated by Arabic numerals may not contain Microtubule-based systemsequal numbers of questions. Intermediate filaments Bacterial flagella and movementI. Cellular and Molecular Biology (33-34%) 7. Cell cycle, growth, division, and regulationFundamentals of cellular biology, genetics, and (including signal transduction)molecular biology are addressed. Major topics in 8. Methodscellular structure and function include metabolic Microscopy (e.g., electron, light,pathways and their regulation, membrane dynamics fluorescence)and cell surfaces, organelles, cytoskeleton, and cell Separation (e.g., centrifugation, gel filtration,cycle. Major areas in genetics and molecular biol- PAGE, Fluorescence activated cellogy include chromatin and chromosomal structure, sorting (FACS))genomic organization and maintenance, and the Immunological (e.g., Western Blotting,regulation of gene expression. The cellular basis of immunohistochemistry, immunofluor-immunity and the mechanisms of antigen-antibody escence)interactions are included. Distinctions between pro- B. Genetics and Molecular Biology (16-17%)karyotic and eukaryotic cells are considered whereappropriate. Attention is also given to experimental 1. Genetic foundationsmethodology. Mendelian inheritance Pedigree analysisA. Cellular Structure and Function (16-17%) Prokaryotic genetics (transformation, 1. Biological compounds transduction, and conjugation) Macromolecular structure and bonding Genetic mapping Abiotic origin of biological molecules 2. Chromatin and chromosomes 2. Enzyme activity, receptor binding, and regulation Nucleosomes 3. Major metabolic pathways and regulation Karyotypes Respiration, fermentation, and photosynthesis Chromosomal aberrations Synthesis and degradation of macromolecules Polytene chromosomes Hormonal control and intracellular messengers 3. Genome sequence organization 4. Membrane dynamics and cell surfaces Introns and exons Transport, endocytosis, and exocytosis Single-copy and repetitive DNA Electrical potentials and transmitter Transposable elements substances 4. Genome maintenance Mechanisms of cell recognition, cell DNA replication junctions, and plasmodesmata DNA mutation and repair Cell wall and extracellular matrix 5. Gene expression and regulation in 5. Organelles: structure, function, synthesis, prokaryotes and eukaryotes: mechanisms and targeting The operon Nucleus, mitochondria, and plastids Promoters and enhancers Endoplasmic reticulum and ribosomes Transcription factors Golgi apparatus and secretory vesicles RNA and protein synthesis Lysosomes, peroxisomes, and vacuoles Processing and modifications of both RNA and protein BIOLOGY TEST 5 PRACTICE BOOK
  6. 6. 6. Gene expression and regulation: effects 3. Support and movement Control of normal development Support systems (external, internal, Cancer and oncogenes and hydrostatic) 7. Immunobiology Movement systems (flagellar, ciliary, and Cellular basis of immunity muscular) Antibody diversity and synthesis 4. Integration and control mechanisms Antigen-antibody interactions Nervous and endocrine systems 8. Bacteriophages, animal viruses, and 5. Behavior (communication, orientation, plant viruses learning, and instinct) Viral genomes, replication, and assembly 6. Metabolic rates (temperature, body size, Virus - host cell interactions and activity) 9. Recombinant DNA methodology B. Animal Reproduction and Development (6%) Restriction endonucleases Blotting and hybridization 1. Reproductive structures Restriction fragment length polymorphisms 2. Meiosis, gametogenesis, and fertilization DNA cloning, sequencing, and analysis 3. Early development (e.g., polarity, cleavage, Polymerase chain reaction and gastrulation) 4. Developmental processes (e.g., induction,II. Organismal Biology (33-34%) determination, differentiation, morpho-The structure, physiology, behavior, and development genesis, and metamorphosis)of plants and animals are addressed. Topics covered 5. External control mechanismsinclude nutrient procurement and processing, gas (e.g., photoperiod)exchange, internal transport, regulation of fluids, C. Plant Structure, Function, and Organization,control mechanisms and effectors, and reproduction with Emphasis on Flowering Plants (7%)in autotrophic and heterotrophic organisms. Exam-ples of developmental phenomena range from fertil- 1. Organs, tissue systems, and tissuesization through differentiation and morphogenesis. 2. Water transport, including absorptionPerceptions and responses to environmental stimuli and transpirationare examined as they pertain to both plants and 3. Phloem transport and storageanimals. Major distinguishing characteristics and 4. Mineral nutritionphylogenetic relationships of selected groups from 5. Plant energetics (e.g., respiration andthe various kingdoms are also covered. photosynthesis)A. Animal Structure, Function, D. Plant Reproduction, Growth, and and Organization (10%) Development, with Emphasis on Flowering Plants (5%) 1. Exchange with environment Nutrient, salt, and water exchange 1. Reproductive structures Gas exchange 2. Meiosis and sporogenesis Energy 3. Gametogenesis and fertilization 2. Internal transport and exchange 4. Embryogeny and seed development (circulatory, gastrovascular, and 5. Meristems, growth, morphogenesis, and digestive systems) differentiation 6. Control mechanisms (e.g., hormones, photoperiod, and tropisms)6 BIOLOGY TEST PRACTICE BOOK
  7. 7. E. Diversity of Life (6%) the molecular, individual, population, and higher levels. Principles of ecology, genetics, and evolution 1. Archaea are interrelated in many questions. Some questions Morphology, physiology, and identification may require quantitative skills, including the inter- 2. Bacteria (including cyanobacteria) pretation of simple mathematical models. Morphology, physiology, pathology, and identification A. Ecology (16-17%) 3. Protista 1. Environment/organism interaction Protozoa, other heterotrophic Protista Biogeographic patterns (slime molds and Oomycota), and Physiological ecology Autotrophic Protista Temporal patterns (e.g., seasonal fluctuations) Major distinguishing characteristics 2. Behavioral ecology Phylogenetic relationships Habitat selection Importance (e.g. eutrophication, disease) Mating systems 4. Fungi Social systems Distinctive features of major phyla Resource acquisition (vegetative, asexual and sexual 3. Population Structure and Function reproduction) Population dynamics/regulation Generalized life cycles Demography and life history strategies Importance (e.g., decomposition, 4. Communities biodegradation, antibiotics, and Direct and indirect interspecific interactions pathogenicity) Community structure and diversity Lichens Change and succession 5. Animalia with emphasis on major phyla 5. Ecosystems Major distinguishing characteristics Productivity and energy flow Phylogenetic relationships Chemical cycling 6. Plantae with emphasis on major phyla Alternation of generations B. Evolution (16-17%) Major distinguishing characteristics Phylogenetic relationships 1. Genetic variability Origins (mutations, linkage, recombination,III. Ecology and Evolution (33-34%) and chromosomal alterations) This section deals with the interactions of organ- Levels (e.g., polymorphism and heritability)isms and their environment, emphasizing biological Spatial patterns (e.g., clines and ecotypes)principles at levels above the individual. Ecologi- Hardy-Weinberg equilibriumcal and evolutionary topics are given equal weight. 2. Evolutionary processesEcological questions range from physiological Gene flow and genetic driftadaptations to the functioning of ecosystems. Al- Natural selection and its dynamicsthough principles are emphasized, some questions Levels of selection (e.g., individualmay consider applications to current environmental and group)problems. Questions in evolution range from its Trade-offs and genetic correlationsgenetic foundations through evolutionary processesto their consequences. Evolution is considered at BIOLOGY TEST 7 PRACTICE BOOK
  8. 8. 3. Evolutionary consequences Following are some general test-taking strategies Fitness and adaptation you may want to consider. Speciation Ⅲ Read the test directions carefully, and work Systematics and phylogeny as rapidly as you can without being careless. Convergence, divergence, and extinction For each question, choose the best answer Coevolution from the available options. 4. History of life Origin of prokaryotic and eukaryotic cells Ⅲ All questions are of equal value; do not waste Fossil record time pondering individual questions you find Paleontology and paleoecology extremely difficult or unfamiliar. Ⅲ You may want to work through the test quitePreparing for a rapidly, first answering only the questions about which you feel confident, then goingSubject Test back and answering questions that require more thought, and concluding with the mostGRE Subject Test questions are designed to measure difficult questions if there is time.skills and knowledge gained over a long period oftime. Although you might increase your scores to Ⅲ If you decide to change an answer, make suresome extent through preparation a few weeks or you completely erase it and fill in the ovalmonths before you take the test, last minute cramming corresponding to your desired unlikely to be of further help. The following infor- Ⅲ Questions for which you mark no answermation may be helpful. or more than one answer are not counted Ⅲ A general review of your college courses is in scoring. probably the best preparation for the test. Ⅲ Your score will be determined by subtracting However, the test covers a broad range of one-fourth the number of incorrect answers subject matter, and no one is expected to be from the number of correct answers. If you familiar with the content of every question. have some knowledge of a question and Ⅲ Use this practice book to become familiar are able to rule out one or more of the with the types of questions in the GRE answer choices as incorrect, your chances Biology Test, paying special attention to the of selecting the correct answer are improved, directions. If you thoroughly understand the and answering such questions will likely directions before you take the test, you will improve your score. It is unlikely that pure have more time during the test to focus on guessing will raise your score; it may lower the questions themselves. your score. Ⅲ Record all answers on your answer sheet.Test-Taking Strategies Answers recorded in your test book will not be counted.The questions in the practice test in this book Ⅲ Do not wait until the last five minutes ofillustrate the types of multiple-choice questions in a testing session to record answers on yourthe test. When you take the actual test, you will answer sheet.mark your answers on a separate machine-scorableanswer sheet. Total testing time is two hours andfifty minutes; there are no separately timed sections.8 BIOLOGY TEST PRACTICE BOOK
  9. 9. What Your Scores Mean Range of Raw Scores* Needed to Earn Selected Scaled ScoreYour raw score, that is—the number of questions on Three Biology Test Editionsyou answered correctly minus one-fourth of the That Differ in Difficultynumber you answered incorrectly—is converted to Raw Scoresthe scaled score that is reported. This conversion Scaled Scoreensures that a scaled score reported for any edition Form A Form B Form Cof a Subject Test is comparable to the same scaled 800 128-130 124-125 120-121score earned on any other edition of the same test. 700 101-103 95-97 92-94Thus, equal scaled scores on a particular Subject 600 74-76 67-69 64-66Test indicate essentially equal levels of performance 500 47-49 39-41 37-39regardless of the test edition taken. Test scoresshould be compared only with other scores on the Number of Questions Used to Compute Raw Scoresame Subject Test. (For example, a 680 on the 199 198 200Computer Science Test is not equivalent to a 680 *Raw Score = Number of correct answers minus one-fourth theon the Mathematics Test.) number of incorrect answers, rounded to the nearest integer. Before taking the test, you may find it usefulto know approximately what raw scores would berequired to obtain a certain scaled score. Several For a particular test edition, there are many waysfactors influence the conversion of your raw score to earn the same raw score. For example, on theto your scaled score, such as the difficulty of the test edition listed above as “Form A,” a raw score ofedition and the number of test questions included 101 through 103 would earn a scaled score of the computation of your raw score. Based on Below are a few of the possible ways in which arecent editions of the Biology Test, the following scaled score of 700 could be earned on the edition:table gives the range of raw scores associated withselected scaled scores for three different test editions.(Note that when the number of scored questions Examples of Ways to Earnfor a given test is greater than the range of possible a Scaled Score of 700scaled scores, it is likely that two or more raw scores on the Edition Labeled as “Form A”will convert to the same scaled score.) The threetest editions in the table that follows were selected Number ofto reflect varying degrees of difficulty. Examinees Questionsshould note that future test editions may be some- Questions Questions Questions Used to Raw Answered Answered Not Computewhat more or less difficult than those test editions Score Correctly Incorrectly Answered Raw Scoreillustrated in the table. 101 101 0 98 199 101 111 39 49 199 101 120 78 1 199 103 103 0 96 199 103 112 37 50 199 103 122 75 2 199 BIOLOGY TEST 9 PRACTICE BOOK
  10. 10. Practice Test To become familiar with how the administration will be conducted at the test center, first remove the answer sheet (pages 69 and 70). Then go to the back cover of the test book (page 64) and follow the instructions for completing the identification areas of the answer sheet. When you are ready to begin the test, note the time and begin marking your answers on the answer sheet.10 BIOLOGY TEST PRACTICE BOOK
  11. 11. FORM GR0624 24 GRADUATE RECORD EXAMINATIONS® BIOLOGY TEST Do not break the seal until you are told to do so. The contents of this test are confidential. Disclosure or reproduction of any portion of it is prohibited.THIS TEST BOOK MUST NOT BE TAKEN FROM THE ROOM. Copyright © 1999, 2003, 2006 by Educational Testing Service. All rights reserved. GRE, GRADUATE RECORD EXAMINATIONS, ETS, EDUCATIONAL TESTINGSERVICE and the ETS logos are registered trademarks of Educational Testing Service. 13
  13. 13. BIOLOGY TEST Time—170 minutes 200 QuestionsDirections: Each of the questions or incomplete statements below is followed by five suggested answers orcompletions. Select the one that is best in each case and then completely fill in the corresponding space on theanswer sheet.1. In the formation of the secondary structure 5. Separation of molecules according to size can be of a protein, which of the following are most achieved by which of the following? responsible for holding an alpha-helix region (A) Gel-filtration chromatography in its helical form? (B) Ion-exchange chromatography (A) Ionic bonds (C) Affinity chromatography (B) Hydrogen bonds (D) Isoelectric focusing (C) Disulfide bonds (E) X-ray diffraction (D) Hydrophobic interactions (E) van der Waals interactions 6. Which of the following is true of the movement of cilia and flagella in eukaryotes?2. Why do erythrocytes swell and burst when placed (A) It produces ATP. in water? (B) It is the result of a rotating motion. (A) Since water concentration is higher outside (C) It is identical to that of bacterial flagella. the cell, water moves inward by passive (D) It is driven by a proton gradient. diffusion. (E) It results from one microtubule pair sliding (B) Since hemoglobin concentration is higher along a neighboring microtubule pair. inside the cell, hemoglobin moves outward by exocytosis. 7. Which of the following is true of the polymerase (C) Since potassium ions are more concentrated chain reaction? inside the cells, potassium ions move (A) It enables a small amount of DNA to be outward by osmosis. amplified. (D) Erythrocytes pump water inward by active (B) It involves the addition of a poly-A sequence transport to balance osmotic gradients. to mRNA. (E) Water is a universal solvent and simply (C) It cuts DNA into numerous small fragments dissolves the erythrocyte membranes. for analysis. (D) It separates DNA fragments according to3. The addition of -amanitin, a known inhibitor size. of DNA-dependent mRNA synthesis, to growing (E) It requires RNA in order to proceed. cells will most likely cause protein synthesis to (A) stop immediately 8. Which of the following pathways is most likely (B) stop as mRNA becomes depleted taken by newly synthesized histones? (C) stop as thymidine becomes depleted (D) stop as the ribosomes become inactivated (A) Rough endoplasmic reticulum → Golgi (E) be unaffected complex → secretory vesicle (B) Rough endoplasmic reticulum → Golgi4. An infectious agent that appears to have no complex → nucleus nucleic acid is a (C) Rough endoplasmic reticulum → smooth (A) bacterium endoplasmic reticulum → nucleus (B) bacteriophage (D) Cytoplasm → nucleus (C) viroid (E) Cytoplasm → rough endoplasmic reticulum (D) virus → Golgi complex → nucleus ( ) (E) p o prion GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 15
  14. 14. 9. How many different types of gametes could be 13. Which of the following is correct concerning the produced by an individual with the arbitrary Km of an enzyme? genotype of AAbbCCDdEe ? (A) It depends on the dissociation constant for the (A) Two product of the reaction. (B) Four (B) It defines the Vmax of the enzyme-catalyzed (C) Six reaction. (D) Eight (C) It is a measure of the number of substrate (E) More than eight molecules converted to product in a specific unit of time.10. During cytokinesis in an animal cell, a constricting (D) It is the substrate concentration at which the ring pinches the dividing cell into the two daughter velocity of the reaction is equal to 1/2 Vmax. cells. This contractile ring is formed by which of the following structures? (E) It is measured in units of moles per minute. (A) Centrioles 14. Which of the following types of enzymes are (B) Microtubules usually subjected to direct feedback inhibition (C) Microfilaments by an intracellular metabolite? (D) Z discs (E) The spindle apparatus (A) Enzymes catalyzing the last step in a catabolic pathway11. If an organic acid accumulates in a plant cell (B) Enzymes catalyzing the last step in a in sufficient quantities to affect the cell’s pH biosynthetic pathway significantly, then the acid will probably be (C) Enzymes catalyzing the first step in a stored in the biosynthetic pathway (D) Enzymes localized in the extracellular matrix (A) cytosol (E) Enzymes localized in lysosomes (B) vacuole (C) nucleus 15. Which of the following cellular structures (D) mitochondria serve similar functions in plants and animals, (E) chloroplasts respectively?12. Which of the following information can be gained Plants Animals from determining the primary structure of an (A) Tight junctions Gap junctions enzymatically active protein? (B) Desmosomes Gap junctions (A) The amino acids in the active site can be (C) Plasmodesmata Gap junctions positively identified. (D) Plasmodesmata Desmosomes (B) The molecular weight of the protein can be (E) Plasmodesmata Tight junctions accurately established. (C) The temperature at which thermal inactivation 16. Increased calcium influx across the membranes of will occur can be accurately established. presynaptic neurons has which of the following (D) An estimate of Km can be calculated. effects on synaptic transmission? (E) An estimate of Vmax can be calculated. (A) Increased release of neurotransmitter (B) Increase in voltage-dependent potassium efflux (C) Decreased release of neurotransmitter (D) Decrease in voltage-dependent potassium efflux (E) Closure of the acetylcholine-gated channel GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal. 16
  15. 15. 19. Which of the following best explains how the activity of an enzyme is regulated by an allosteric inhibitor? (A) Direct competition between the binding of the inhibitor and the binding of a substrate to the active site (B) Induction of a conformational change in the17. The tubulin heterodimer depicted above is located enzyme by the inhibitor, which affects within a protofilament of an intact microtubule. enzyme activity To which site is the portion of its neighboring (C) Irreversible binding of the inhibitor to the heterodimer (within the same protofilament) enzyme, which affects enzyme activity attached? (D) Inhibition of the transcription of the gene encoding the enzyme by the inhibitor (A) L (E) Denaturation of the protein induced by (B) M binding of the inhibitor (C) N (D) O 20. A species of plant is discovered in which (E) P individual plants produce either white or purple flowers. True breeding plants that have short stems with white flowers are crossed with true breeding plants that have tall stems and purple flowers. The resulting offspring all have tall stems with purple flowers. When one of these tall, purple-flowered offspring is crossed with a short, white-flowered plant, plants with the following characteristics were obtained in equal proportions. White flowers on tall stems Purple flowers on tall stems White flowers on short stems Purple flowers on short stems18. During meiosis, homologous chromosomes pair up along their lengths. The most plausible Given the information above, which of the explanation for the karyotype structure shown following is most likely true? above is that (A) The white-flower allele and the tall-stem (A) portions of non-homologous chromosomes allele occur at the same locus. have been translocated (B) The genes for flower color and stem length are closely linked. (B) one of the two homologous chromosomes has suffered a deletion (C) Extensive crossing-over between the (C) one of the two homologous chromosomes purple-flower allele and the white-flower allele has occurred. has undergone an inversion (D) the homologous chromosomes have each (D) The genes for flower color and stem length suffered a gene duplication are not linked. (E) one of a pair of homologous chromosomes (E) Independent assortment does not occur in has been lost via nondisjunction this species of plant. GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 17
  16. 16. 21. An X-linked recessive gene produces red-green 25. In nerves, vesicles can move the length of an color blindness in humans. A woman with normal axon at a rate that far exceeds that which would color vision whose father was color-blind marries be predicted for simple diffusion. Which of the a color-blind man. What is the probability that following models best explains vesicular their son will be color-blind? movement in these cells? (A) 0 (A) Depolymerization of actin microfilaments (B) 1/4 attached to vesicles pulls the vesicles (C) 1/2 toward the site of depolymerization. (D) 3/4 (B) Vesicles are propelled by fluid movement (E) 1/1 generated by changes in osmotic potential within the cells.22. Which of the following is NOT a correct statement (C) Vesicles are moved by alternate contraction about the process of meiosis? and relaxation of actin-myosin “muscle” complexes. (A) Meiosis I separates chromosomes; meiosis II (D) Vesicles, by virtue of their net negative separates chromatids. charge, are attracted to positively charged (B) Synapsis and crossing-over occur during regions of the cell. meiosis I. (E) Vesicles are attached to the protein kinesin, (C) Kinetochores are responsible for aligning which slides along microtubules by an ATP- chromatids during meiosis I. dependent process. (D) Karyokinesis occurs before cytokinesis. (E) Segregation of unlinked alleles occurs during 26. Additions or deletions of bases in the nucleotide meiosis. sequence of a structural gene most often result in23. Endoplasmic reticulum (ER) is the site of all of (A) an altered sequence of amino acids in the the following EXCEPT protein that the gene encodes (B) insertion of a new intron into the coding (A) drug detoxification by means of mixed- sequence of the gene function oxidases (C) decreased histone binding (B) synthesis of proteins that are secreted from (D) decreased excision repair the cell (E) increased levels of mRNA production (C) N-linked glycosylation of newly formed polypeptides 27. Radioactive cytosine was added to an actively (D) Ca2+ storage in muscle tissues growing culture of E. coli bacteria. Which of the (E) hydrolytic activities carried out by acid following would be the result if a cell replicated hydrolases once in the presence of this radioactive base?24. Exons of a gene are defined as (A) One of the daughter cells, but not the other, would have radioactive DNA. (A) the untranslated regions of the corresponding (B) Neither of the two daughter cells would mRNA have radioactive DNA. (B) regions in the corresponding mRNA that are (C) Both daughter cells would have involved in initiation of transcription radioactive DNA. (C) regions that are not transcribed by RNA (D) Radioactive cytosine would pair with polymerase nonradioactive adenine during DNA (D) regions that are excised from the corre- replication. sponding protein after it is synthesized (E) DNA replication would not occur, because (E) regions that remain in the corresponding two radioactive bases are required for mRNA after splicing proper pairing. GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal.18
  17. 17. 28. Which of the following is an anticodon? 31. In Drosophila, regions of polytene chromosomes show puffs at different times in development. (A) The part of a DNA molecule that codes for Studies with labeled compounds have indicated chain termination that the localization to the puffs of tritiated (B) A 3-nucleotide sequence of an mRNA molecule (A) thymidine indicates that DNA is being (C) A specific part of a tRNA molecule synthesized (D) A nucleotide triplet of an rRNA molecule (B) thymidine indicates that RNA is being (E) The portion of a ribosomal subunit that synthesized interacts with aminoacyl-tRNA synthetase (C) leucine indicates that new proteins are being synthesized29. Drosophila lines with large, sometimes multiple, (D) uridine indicates that DNA is being inversions in one or more chromosomes are often synthesized used in maintaining laboratory stocks because (E) uridine indicates that RNA is being of which of the following reasons? synthesized (A) Inversions maximize the process of 32. In Drosophila, a homeotic mutation would be chromosome pairing within and near the most likely explanation for which of the the inversion. following? (B) Inversions in the male inhibit fertilization of non-inversion-containing females. (A) A decrease in the number of parasegments (C) Inversion heterozygotes produce a greater (B) A leg developing where an antenna would number of viable offspring. normally be located (D) Inversion heterozygotes usually yield (C) Forked and dense body bristles instead of inviable gametes or zygotes when straight and sparse ones crossing-over occurs within the inversion. (D) A significantly shorter life span (E) Inversion heterozygotes produce a greater (E) An increase in wing length number of recombinant offspring. 33. Humoral immunity is characterized by all of the30. Chimeric mice can be generated by injecting a following EXCEPT cell from an early embryo into a blastocyst of (A) a memory response another genotype. The fact that the single injected (B) antigen-antibody interaction cell can contribute to many tissues of the chimeric (C) the synthesis of immunoglobulins mouse has led to the conclusion that cells of the (D) the production of plasma cells early embryo are (E) the production of cytotoxic T cells (A) differentiated (B) motile (C) transformed (D) transduced (E) totipotent GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 19
  18. 18. 34. The immune system in mammals can rapidly 36. In adult mammals, the primary site for the final respond to foreign molecules because of the stage of differentiation of T lymphocytes is the enormous variety of B lymphocytes, each with (A) spleen different cell-surface antibodies that can bind (B) bone marrow specific antigens. Which of the following best (C) bursa of Fabricius explains the principal mechanism by which the (D) thymus diversity of lymphocytes arises? (E) liver (A) During the development of B lymphocytes, rearrangements of the DNA coding for the 37. In the DNA sequence 5 CGA TCG GCT 3 , various domains of the antibody molecule which of the following is considered a transition- occur. type mutation? (B) During the development of B lymphocytes, different introns are spliced out of antibody (A) 5 CGA CCG GCT 3 mRNA’s. (B) 5 CGA TGG CT 3 (C) mRNA’s for all 1015 types of antibodies are (C) 5 CGA TCG CCT 3 produced by each B lymphocyte; however, (D) 5 CGA TCG GCA 3 only one type of mRNA gets translated. (E) 5 CGA UCG GCU 3 (D) All 1015 types of antibodies are produced by each B lymphocyte; specific proteases 38. Artificially acquired passive immunity involves degrade all but one type. (E) Different B lymphocytes carry different (A) vaccination with attenuated virus or bacteria transcription activators, so that only one (B) the transfer of antibodies, as from a mother to specific mRNA (and therefore, antibody) is her fetus produced by each lymphocyte. (C) the production of a cellular immune response or antibodies35. Hybridization between mature mRNA and DNA (D) antibody formation as a result of exposure to can identify introns in eukaryotic genes. When antigens in the environment mature mRNA produced by the insulin gene is (E) injection of preformed antibodies such as hybridized with denatured chromosomal DNA, immunoglobulin which of the following will most likely be observed? 39. Which of the following is true concerning animal retroviruses? (A) No hybridization would occur under any conditions. (A) They must replicate during the S phase of (B) Hybridization of mRNA would occur with the cell cycle. random sections of chromosomal DNA. (B) They require an RNA-dependent DNA (C) Hybridization of mRNA with DNA would polymerase. occur in a continuous stretch that is equal (C) They are nonenveloped viruses. to the length of the mRNA. (D) The virions have double-stranded RNA (D) Hybridization of mRNA with DNA would genomes. occur but with many single-stranded loops (E) Replication of their genome occurs entirely of DNA. within the host nucleus. (E) Hybridization of mRNA with DNA would occur but with many single-stranded loops of mRNA. GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 20
  19. 19. 40. In Escherichia coli, the synthesis of tryptophan Type I: slow, oxidative, red is controlled by the tryptophan operon that is Type II A: fast, oxidative, red repressed in the presence of excessive tryptophan. Type II B: fast, glycolytic, white When a mutant strain that has lost the regulatory gene of the tryptophan operon is placed in a 43. The muscle cells listed above will most likely medium that contains all nutrients the cells need fatigue in what order, from first to last? to grow except tryptophan, which of the following First Last will occur? (A) Type I Type II A Type II B (A) The cells will continue to grow even (B) Type I Type II B Type II A though excess tryptophan is synthesized. (C) Type II A Type I Type II B (B) The cells will grow until excessive (D) Type II B Type II A Type I tryptophan arrests the expression of the (E) All three types will fatigue at the same rate. operon. (C) The cells will not grow until enough 44. Members of which of the following terrestrial tryptophan has been synthesized to activate groups have the most water-permeable body the corepressor. covering? (D) The cells will never grow unless tryptophan is added to the medium. (A) Insecta (E) The cells will not grow even when (B) Reptilia tryptophan is added to the medium. (C) Aves (D) Arachnida41. Which of the following is LEAST likely to cause (E) Amphibia a proto-oncogene to become an oncogene? 45. Which of the following is found in mammals (A) A gene is incorporated into a retroviral during male gamete formation? genome. (B) A gene is expressed at an inappropriate time. (A) Two successive centrosome duplications (C) A gene is moved close to an enhancer, during meiosis causing excess product to be made. (B) Accumulation of yolk during gamete (D) A gene is truncated, yielding a protein with formation modified activity. (C) Generation of a polar body during meiosis I (E) A gene is moved into centromeric (D) Formation of four functional gametes from a heterochromatin, silencing its transcription. primary germ cell (E) Temporary arrest of meiosis at the42. The physiological role of restriction metaphase I stage endonucleases is to (A) allow the in vitro construction of recombinant DNA molecules (B) methylate host DNA (C) remove RNA primer during DNA synthesis GO ON TO THE NEXT PAGE. (D) allow mapping of gene location (E) cleave foreign DNA molecules that enter the cell Unauthorized copying or reuse of any part of this page is illegal. 21
  20. 20. 46. During the evolution of life on Earth, the photo- 50. Chickadees were given an opportunity to store synthetic organisms initially responsible for seeds in 72 possible storage sites consisting of raising atmospheric oxygen concentrations from holes drilled in small trees that had been placed less than 1 percent to about 20 percent were in an aviary. Typically, the seeds were placed in only 4 or 5 storage sites. The chickadees were (A) cyanobacteria then removed from the aviary, the seeds removed (B) archaea from the storage sites, and each hole covered. (C) diatoms A day later, the chickadees were returned to the (D) flowering plants aviary and they spent nearly 5 times as long (E) mosses pulling at the covers on storage sites than at the covers on sites where they had not stored food.47. Which of the following statements about circadian This experiment indicates that chickadees rhythms is correct? (A) use auditory cues to find stored food (A) They are expressed during cell division only. (B) have a spatial memory that enables them (B) They occur only in mammals. to locate storage sites (C) They are not found in humans. (C) have a propensity to inspect and pull at the (D) They are generated exogenously. covers wherever they are located (E) They have a periodicity of about 24 hours. (D) cannot find a storage site if they cannot see the food in it48. The receptive surface for pollen on an angiosperm (E) rely on the visual cues provided by the flower is the opening to a storage site to locate (A) anther stored food (B) corolla (C) ovary 51. Bird species X stores seeds in a large number of (D) style separate caches in the summer and then locates (E) stigma the caches in the winter. Compared with a bird species that does not store seeds, species X can49. Immediately after fertilization in animals, the first be expected to have a proportionately larger structural and biochemical changes in the egg are (A) cerebellum initiated by (B) hippocampus (A) new gene transcription (C) optic lobe (B) the release of Ca2+ from internal reservoirs (D) hypothalamus (C) the initiation of DNA synthesis (E) medulla (D) a lowering of cytosolic pH (E) a sudden drop in ATP levels 52. Functionally, Hensen’s node is to a chick embryo as the (A) animal pole is to a frog embryo (B) blastopore dorsal lip is to a frog embryo (C) ectoderm is to a bird embryo (D) vegetal pole is to a frog embryo (E) anterior pole cells are to a Drosophila embryo GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal.22
  21. 21. 53. The oxygen consumption of marine crabs acclimated to either 10°C or 20°C was measured at environmental temperatures of 5°C to 25°C to produce the following graph. Which of the following can be correctly concluded from the information in the graph? (A) Acclimation temperature does not affect the rate of oxygen consumption. (B) Crabs have higher rates of oxygen consumption when measured at 10°C than when measured at 20°C. (C) Oxygen consumption is higher in the 10°C-acclimated crabs than in the 20°C-acclimated crabs at each test temperature. (D) Acclimation to a high temperature induces a high rate of oxygen consumption at all test temperatures. (E) This pattern of acclimation produces complete metabolic compensation. GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal. 23
  22. 22. 54. The outermost tissue of a tree trunk that is 6 feet 56. Which of the following cells or tissues are in diameter would most likely be characteristically found in the roots, but not the stems, of angiosperms? (A) epidermis (B) cork (A) Parenchyma and collenchyma (C) cortex (B) Epidermis and cork (D) phloem (C) Pericycle and endodermis (E) xylem (D) Vessel elements and tracheids (E) Sieve tube members and companion cells55. Which of the following is the tissue that is most important in plant survival during droughts and why? (A) Vascular tissue, because the phloem keeps the plant supplied with water (B) Vascular tissue, because the xylem can store considerable amounts of water (C) Ground tissue, because water can be stored in the sclerenchyma for use during droughts (D) Ground tissue, because the parenchymal tissue provides hormonal cues to stop water loss (E) Epidermal tissue, because it is covered with a waxy cuticle and includes drought- responsive stomata Species Stomataؒmm−2 on Leaves Upper Epidermis Lower Epidermis Encelia farinosa 248 355 Haworthia attenuata 15 25 Bursera latiflora 0 272 Scilla violaceae 3 35 Agave deserti 40 32 57. The data above were collected from plants growing in the desert of southwest Arizona. Which species probably under- goes the most evaporative cooling in this environment? (A) Encelia farinosa (B) Haworthia attenuata (C) Bursera latiflora (D) Scilla violaceae (E) Agave deserti GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 24
  23. 23. 58. A piece of prospective belly epidermis of a newt 61. In a plant growing vigorously under normal neurula-stage embryo is grafted to the prospective conditions without water stress, in which tissue mouth region of a frog neurula, replacing the frog would you expect to find the lowest (most epidermal tissue at that spot. The grafted embryo negative) water potential? continues to develop and forms a newt mouth and (A) Root epidermal cell teeth at the position of the graft. This result is (B) Root cortical parenchyma consistent with which of the following? (C) Root endodermis (A) Newt tissue develops autonomously (D) Stem xylem according to its original fate, despite its new (E) Leaf mesophyll parenchyma location in the frog embryo. (B) Newt tissue dedifferentiates whenever it is 62. In organisms with closed circulatory systems, grafted. fluid leaves the blood of capillary networks at (C) Tissues of the frog neurula induce the newt the arterial end and returns to blood at the venous tissue to express frog-specific genes that it end for which of the following reasons? would not normally express. (A) Osmotic pressure increases prior to (D) The mouths and teeth of frogs and newts are dehydration. the same in type. (B) Osmotic pressure difference dominates at the (E) The frog tissues of the neurula induce the arterial end; hydrostatic pressure difference newt tissue to form mouthparts. dominates at the venous end. (C) Hydrostatic pressure difference dominates at59. Some chemoautotrophic bacteria living around the arterial end; osmotic pressure difference deep-sea vents obtain their energy by converting dominates at the venous end. (A) alcohols to aldehydes (D) Hydrostatic pressure drops during diastole. (B) hydrogen sulfide to elemental sulfur (E) Hydrostatic pressure difference dominates at (C) carbon dioxide and hydrogen to methane both the arterial and the venous ends. (D) iron oxides to iron (E) nitrogen to ammonia 63. Which of the following mineral nutrients is directly involved in light absorption during60. The ability of a desert rodent’s kidneys to form photosynthesis? highly concentrated urine is largely attributable to (A) Zn2+ (A) a high glomerular filtration rate (B) Mn2+ (B) the production of a very salty ultrafiltrate in the glomerulus (C) Cu2+ (C) the ability of cells lining the proximal (D) Mg2+ convoluted tubule to absorb water (E) Ca2+ (D) long loops of Henle that pass through tissues of increasing salt concentrations (E) distal convoluted tubules that are impermeable to water GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 25
  24. 24. 64. Most of the dry mass of a plant is derived from 67. If the egg cell of a megagametophyte of a flow- ering plant has a marker gene designated as X (A) minerals from the soil and the sperm cell of a compatible pollen grain (B) carbon from the soil has a marker gene designated as Y, which of the (C) carbon from the atmosphere following represents the endosperm that will (D) oxygen from the atmosphere result from fertilization in most flowering plants? (E) oxygen from soil water (A) XX65. Chlorophylls a and b are two pigments primarily (B) YY responsible for the capture and processing of solar (C) XY energy in the light reactions of photosynthesis. (D) XXY Which of the following best explains why having (E) YYX both chlorophyll a and b benefits a plant more than having one? 68. Ca2+ is important in skeletal muscle contraction (A) Chlorophylls a and b have slightly different because it absorption spectra; this expands the range of (A) activates the myosin ATPase by binding to it wavelengths of light that can be captured (B) binds to troponin to remove a constant for photosynthesis. inhibition of cross-bridge attachment (B) Chlorophyll a is primarily involved in (C) prevents the formation of bonds between the electron transfer; chlorophyll b is mainly myosin cross bridges and the actin filament involved in the capture of light energy. (D) is required to detach the myosin head from (C) Chlorophyll a captures all the solar energy; chlorophyll b serves to protect the actin filament chlorophyll a from overexcitation. (E) causes muscle relaxation at intracellular (D) Chlorophyll b captures all the solar energy; concentrations of Ca2+ higher than 10−6M since chlorophyll a is a precursor to chlorophyll b, a pool of chlorophyll a must 69. Which of the following structures present in the be maintained. embryos of higher plants develops into the primary (E) Chlorophyll a resides in the thylakoid root of the seedling? membranes and captures light energy there; (A) Epicotyl chlorophyll b is soluble in the chloroplast (B) Hypocotyl stroma and captures light energy there. (C) Cotyledon (D) Radicle66. The Calvin cycle, the “dark reactions” or carbon (E) Endosperm fixation reactions of photosynthesis, cannot occur at night in a living plant. Which of the following 70. Which of the following statements about the best describes why this is true? motility of Paramecium is true? (A) The stomata are incapable of opening at (A) Paramecium employs a pseudopod. night, thus CO2 cannot enter the leaf. (B) Paramecium has no structures for motility. (B) The reactions of the Calvin cycle are depen- (C) Paramecium uses a single flagellum. dent on light reactions for high-energy (D) Paramecium uses a pair of flagella. compounds. (E) Paramecium uses cilia. (C) Several enzymes necessary for Calvin cycle activity have been degraded during the day and must be replaced. (D) Light is required to transport the water necessary for the cycle. (E) Cooler temperatures at night slow enzyme activity and rates of substrate diffusion. GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 26
  25. 25. 71. In the cellular slime molds, the aggregation of 76. Which of the following animal phyla is myxamoebas is initiated by diploblastic, that is, exhibits only two embryonic germ layers? (A) low light intensities (B) high pH (A) Rotifera (C) uptake of chloride ion (B) Mollusca (D) secretion of cyclic AMP (C) Nematoda (E) elevated temperature (D) Platyhelminthes (E) Cnidaria72. A unicellular eukaryote that contains chlorophyll a (but no chlorophyll b), that functions as one of 77. Which of the following describes members of the major photosynthetic autotrophs in open-ocean both the Bryophyta and the Pteridophyta? ecosystems, and that has cell walls that contain (A) The absence of true roots silica is a (B) The absence of swimming sperm (A) red alga (C) The absence of meristematic growth (B) green alga (D) The presence of chlorophyll (C) dinoflagellate (E) The dominance of the haploid phase of the (D) euglenoid life cycle (E) diatom 78. In sporophytes of some mosses, a ring of73. Dikaryotic hyphae are a kind of fungal tissue that peristome teeth regulates (A) contain two chromosomes (A) sperm release (B) form after plasmogamy and before (B) spore dispersal karyogamy (C) spore germination (C) are only a short stage of the life cycle of the (D) asexual reproduction Basidiomycota (E) rhizoid production (D) are not found in the Ascomycota (E) are formed by the fusion of two nuclei 79. Which of the following characterizes dicoty- ledonous plants?74. Saprophytic fungi obtain their nutrition by (A) Their flowers always have superior ovaries. (A) taking food into their gastrovascular cavity, (B) Their seeds usually contain two embryos. and then digesting and absorbing it (C) Their stems have scattered vascular bundles. (B) making food by chemosynthesis (D) Their leaves usually have parallel veins. (C) secreting digestive enzymes into the (E) Their flowers usually have parts in multiples environment and then absorbing the of four or five. digestive products (D) using their amoeboid cells in phagocytosis 80. All of the following allow hermaphroditic animal (E) forming a parasitic relationship with soil species to avoid inbreeding EXCEPT bacteria (A) functioning as only one sex during mating (B) releasing eggs and sperm simultaneously75. An animal with a coelom, jointed appendages, (C) being protandrous and metameric segmentation would be classified (D) being protogynous in the phylum (E) changing sex (A) Mollusca (B) Cnidaria (C) Platyhelminthes (D) Arthropoda GO ON TO THE NEXT PAGE. (E) Chordata Unauthorized copying or reuse of any part of this page is illegal. 27
  26. 26. 81. All of the following occur during the cleavage 85. The amount of energy entering a food chain stage of animal development EXCEPT depends on the (A) an increase in the nuclear-to-cytoplasmic (A) direction of energy flow in the system ratio of the cells (B) efficiency of energy recycling in the system (B) an increase in the number of blastomeres (C) biomass of carnivores and their efficiency in (C) an increase in the mass of the embryo locating and capturing animal prey (D) an increase in the surface-to-volume ratio of (D) biomass of heterotrophs and their efficiency the cells in transforming plant tissue into animal (E) rapid cell divisions tissue (E) biomass of autotrophs and their efficiency in82. Plants that utilize photosynthesis via the C4 transforming solar energy into chemical pathway differ from those that use the C3 pathway energy in that at higher temperatures the C4 plants 86. Two plant species co-occur in a prairie. Species X (A) are less productive per unit area of leaf always occurs near species Y. However, species Y (B) are more productive per unit area of leaf often occurs in isolation from species X and (C) can tolerate lower light conditions better produces more seeds when alone than when (D) carry on high levels of photorespiration growing next to species X. Which of the (E) use much more water for transpiration per following interactions between species X and Y unit of photosynthesis could generate this pattern? (A) Competition, in which Y is superior to X in83. A lateral root forms on the primary root of a accumulating resources typical herbaceous dicot by (B) Mutualism, in which both X and Y benefit (A) continued growth of a root hair on an by exchanging resources epidermal cell (C) Parasitism, in which X benefits from (B) lateral outgrowth of xylem resources produced by Y and reduces the (C) lateral outgrowth from the root apical growth of Y by doing so meristem (D) Commensalism, in which X benefits from (D) activation of a lateral bud at a node on the resources produced by Y but does not affect surface of the root the growth of Y by doing so (E) activation of an area in the pericycle to form (E) Amensalism, in which X gains no benefit an apical meristem from Y but reduces the growth of Y84. The leaves of grasses can continue to elongate 87. In the endosymbiont hypothesis for the origin following mowing or grazing due to actively of eukaryotic cells, which of the following is growing tissue at the base of the leaf blades and proposed as the role of cyanobacteria? sheaths called (A) They become the chlorophyll of plant cells. (A) apical meristems (B) They are the ancestor of mitochondria. (B) lateral cambium (C) They are the ancestor of the chloroplasts. (C) intercalary meristems (D) They lose their DNA and become the (D) axillary buds vacuoles of plant cells. (E) interfascicular parenchyma (E) They lose their photosynthetic pigments and become the nuclei of eukaryotes. GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 28
  27. 27. 88. The process of speciation can be prevented by (A) genetic differentiation (B) geographical barriers (C) inhibition of gene exchange (D) gene flow (E) behavioral barriers89. Small body size often allows animals to exploit desert habitats because it (A) decreases the ratio of surface area to volume and hence the tendency to lose water 92. The graph above illustrates a simplified description (B) promotes heat gain of the effect of disturbance on species diversity. (C) enhances thermal inertia Which of the following best explains the graph? (D) enables exploitation of favorable microhabitats (A) Productivity is enhanced at intermediate (E) enables prolonged reliance on internal water levels of disturbance. stores (B) Stabilizing selection occurs at intermediate levels of disturbance.90. All of the following are strategies used by (C) The interaction of physical factors and potential prey to avoid predation EXCEPT biological competition increases diversity at intermediate levels of disturbance. (A) mimetic coloration (D) Directional selection is enhanced by (B) erratic flight increased disturbance. (C) cryptic coloration (E) Food chains are disrupted at high and low (D) lekking levels of disturbance. (E) alarm signals 93. Plants having C4 metabolism are common in all91. The amount of genotypic variation in a natural of the following regions EXCEPT population can be increased by all of the following EXCEPT (A) taiga (B) warm deserts (A) mutation (C) tropical grasslands (B) recombination (D) tropical agricultural areas (C) immigration (E) deserts with limited trace elements (D) hybridization (E) inbreeding GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 29
  28. 28. 94. The graphs above show that the relationship between atmospheric CO2 and mean global temperature is (A) a positive correlation (B) an inverse relationship (C) a cause-and-effect relationship (D) evidence of an impending ice age (E) no relationship at all 95. Which of the following is NOT a hypothesis explaining the advantage of group living? (A) Vigilance effect (B) Dilution effect (C) Group foraging (D) Group defense (E) Parasite avoidance GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal.30
  29. 29. 96. The graphs above show the survivorship and fecundity curves for two congeneric species, X and Y, that are found in different habitats. Of the two species, Y is more likely to (A) come from a disturbed habitat in early succession (B) have a longer generation time (C) have a lower fecundity (D) have a longer life span (E) have low dispersal ability GO ON TO THE NEXT PAGE.Unauthorized copying or reuse ofany part of this page is illegal. 31