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AGR 3303 (3 credits) University of Florida - Fort Lauderdale  |
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| Below is Final Exam Part III for 1993, Advanced
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AGR 3303 - Genetics 13 Dec1993 University of Florida - Fort Lauderdale Final Exam PART III (ADVANCED) Multiple choice. Read these carefully. One and only one response (a, b, c, d, or e) most completely and correctly answers the question, or completes the statement. Circle the appropriate response on the separate grading sheet. (26 pts)
PLEASE USE SEPARATE GRADING SHEET 1. Parent plants with the genotypes AABBCC and aabbcc were crossed, and their F1 progeny were backcrossed to a homozygous recessive tester. The 1000 backcross progeny had the phenotypic distribution: Phenotype ABC abc ABc abC AbC aBc aBC Abc Number 400 400 45 45 45 45 10 10 What is the map distance between A and B? a 4.5 map units b 5.5 map units c 9 map units d 11 map units e 22 map units 2. Pleiotropy is: a One gene affects two or more traits. b One trait is affected by two or more genes. c One trait is masked by another. d A situation of incomplete expression. e A defect in collagen. 3. A nucleotide substitution may be undetected because: a the code is degenerate b a new amino acid is coded at an unimportant location c there are two copies of the gene d all of the above e none of the above 4. A cross between two homozygotes will lead to: a a narrow distribution of F1 heterozygotes b a broad distribution of F1 heterozygotes c homozygous progeny d two progeny peaks e none of the above 5. The 128 descendants of our four shipwreck victims have reached Hardy-Weinberg equilibrium. Unfortunately, one of the original four founders of this population had been heterozygous for a recessive allele which controls allergy to coconut, the only available food source. Assuming that the homozygous condition is not fatal, and does not affect reproduction, how many of the descendant population will be allergic to coconut? a 1 b 2 c 4 d 8 e 16 6. Mutations are: a nucleotide substitutions b changes in the allelic condition of genes c rare events d all of the above e none of the above 7. Qualitative traits: a are controlled by many genes b are probably typical of most genes c are subject to continuous variation d are the kinds observed by Mendel e all of the above 8. Regulatory genes in eukaryotes: a function because of simultaneous transcription and translation b code for the primary structure of the enzymes c respond to hormone/receptor protein complexes d all of the above e none of the above 9. Posttranscriptional control is a method: a for amplifying genes b of gene regulation by bacteria and viruses (prokaryotes) c of gene regulation by eukaryotes d all of the above e none of the above 10. Heterochromatin is the part of the chromosome that is: a densely stained b genetically inactive c tightly coiled d protected from enzymatic action e all of the above 11. Genes are: a predispositions b blueprints of what the organism will be c a blend of environmental factors d none of the above e all of the above 12. In the lac operon: a there is a gene which promotes the synthesis of lactose b lactose enables the repressor to bind to the operator c lactose prevents the repressor from binding to the operator d lactose represses the transcription of structural genes e posttranscriptional control reduces unnecessary enzyme production 13. Mutations are important in evolution because: a. they are directional, that is, they occur as a result of natural selection b. they can lead to rapid replacement of normal alleles c. they provide the raw material for genetic drift d. all of the above e. none of the above
Short answer. (6 pts) What biological characteristics of the human immunodeficiency virus (HIV), the cause of AIDS, make the virus so stubborn to control through either drugs or the body's natural defenses? List at least two characteristics discussed in class and explain how the characteristic makes the virus stubborn, in thirty words or less.
PLEASE USE SEPARATE GRADING SHEET Crossword puzzle. Find a word which correctly matches each statement. (18 pts) Enter the correct word for each item in the appropriate spaces. ACROSS 1 A gene associated with uncontrolled cell growth, e.g., cancer. 5 Long-term process of genetic change in an organism; believed to be the origin of new species. 6 The number of genes controlling a trait in which the extreme genotype represents 1/64 of the progeny from a heterozygote. 7 The process of determining the order of nucleotides. 8 A microorganism constructed for transferring a DNA fragment to another organism. 10 An artificial method of amplifying DNA (abbreviation). 11 A measure of parent-offspring resemblance; also, a measure of the degree to which observed phenotypic differences are due to genes, i.e., VG/VP. 14 A piece of DNA, e.g., a result of restriction endonuclease activity. 15 This is what a fragment of DNA, such as a probe, does when its sequence matches another piece of DNA, such as a target; A matches with T, G matches with C. 16 Random loss of alleles or other genetic variations due to small populations. 17 A predictable measure of dispersion in a bell-shaped distribution.
DOWN 1 A genetic unit consisting of structural (e.g., enzyme-coding) and operator (regulator) genes. 2 A reciprocal exchange of genetic material between two chromatids; occurs during pairing at meiosis. 3 This activity must be random, in order for Hardy-Weinberg equilibrium to be maintained. 4 A region of DNA which turns an adjacent gene "on" or "off", due to interaction with a repressor protein. 9 A value determined from a sample; estimates the parameter of a population; also used in evaluating the uncertainty of inductive inferences. 12 A DNA strand which is copied, e.g., by the polymerase chain reaction (PCR). 13 A system of chemical warfare practiced by the cell; involves antibodies.
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