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AGR 3303 (3 credits) University of Florida - Fort Lauderdale  |
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| Below is Final Exam for 1994 |
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AGR 3303 - Genetics 12 Dec 1994 University of Florida - Fort Lauderdale
True or false? (50 pts.) Each statement is either true or false. Telling only part of the truth does not make a statement false. Please circle T for true or F for false. 1. T F A gene can be defined as a unit factor of inheritance. 2. T F Consider a gene with three alleles. In a diploid organism, there are four possible genotypes. 3. T F A man with type A blood can be the father of a child with type B blood. 4. T F Mutations can cause cancer by converting genes that regulate cell growth to a permanently "turned on" condition. 5. T F HIV, human immunodeficiency virus, infects the red blood cells 6. T F In a population, if you know the frequency of genotypes, you can predict the frequency of gametes. 7. T F A class of molecules that distinguishes among different codons is a ribosome. 8. T F The human male always receives his X chromosome from his mother. 9. T F Because of redundancy, RNA homopolymers code for more than one amino acid. 10. T F The shift in peppered moths to a darker color, during the industrial revolution, is evidence for the presence of Hardy-Weinberg equilibrium. 11. T F If an organism has 2n=46, then during mitosis there will be 23 chromosomes going to each pole. 12. T F A polypeptide is a large molecule made up of amino acids. 13. T F If a man has hemophilia, caused by a recessive sex-linked allele, then there is 50% chance his son will have the same disease. 14. T F In the lac operon lactose binds with the repressor protein. 15. T F An antibody is a foreign substance which leads the body to produce antigens. 16. T F Nitrogenous base pairs are held together by hydrogen bonds. 17. T F Down syndrome is caused by one extra chromosome. 18. T F The mitochondrion is the site of photosynthesis. 19. T F Darwin questioned the fixity of species. 20. T F Your teacher is euploid. 21. T F Mutations involve DNA base substitution. 22. T F Mitosis is a reduction division. 23. T F An dominant allele is only expressed when it is present in two copies. 24. T F The four characteristics of the genetic material are replication, expression, storage, and mutation. 25. T F Retroviruses are RNA viruses which use reverse transcriptase to make a DNA "copy" of their RNA. 26. T F The Broward Sheriff's lab does DNA fingerprinting by a method involving restriction endonucleases. 27. T F Frameshift mutations are caused by a nonsense codon. 28. T F The histocompatibility antigens of the HLA complex are involved with tissue graft rejection. 29. T F Assumptions underlying Hardy-Weinberg equilibrium are random mating, no selection, no migration, no mutation, and large population size. 30. T F Mitochondria may be ancient cell invaders. 31. T F The alleles determining human ABO blood types are an example of polygenes. 32. T F Plant breeders would prefer that heritability be high. 33. T F A gene can be defined as a chemical factor of inheritance. 34. T F Whenever P < 0.05, this means we can be 95% certain that the null hypothesis is true. 35. T F Heterochromatin constitutes genetically inactivated chromosome regions. 36. T F Eukaryotic gene regulation involves simultaneous transcription and translation. 37. T F DNA polymerase is active in transcription. 38. T F If the single-stranded DNA sequence is 5' AAG 3', then the mRNA sequence is 5' CTT 3'. 39. T F The Central Dogma deals with mutation. 40. T F Linkage is consistent with the idea that genes are carried on chromosomes. 41. T F Epistatic, interacting loci express the 9:3:3:1 ratios observed by Mendel. 42. T F Heritability is the ratio of phenotypic variance divided by genotypic variance. 43. T F The bacteria of Avery et al. (1944) were transformed by a substance which remained active after treatment by DNase. 44. T F In replication, the daughter DNA is composed of two new strands. 45. T F A mutant allele can be recessive because it is masked by another gene. 46. T F Population genetics does not involve qualitative traits. 47. T F The basic unit of double-stranded DNA is a nitrogenous base. 48. T F Heat-killed virulent bacteria have a substance which transforms avirulent bacteria into becoming virulent. 49. T F Complementarity is important in translation. 50. T F Enzymes occur in the nucleus.
Multiple choice. (45 pts.) Please read these carefully. Only one response correctly answers the question, or completes the statement. Circle the corresponding letter (a, b, c, d, or e). 51. Coat color of the female house cat can be a mosaic of different colored patches. What is the most plausible genetic hypothesis for this phenomenon? a. mutations b. codominance c. incomplete dominance d. random inactivation of the X-chromosome e. none of the above could explain the observations 52. A chi-square value was calculated from a genetics experiment, based on a comparison of observed phenotypes with their 3:1 expected distribution based on Mendelian genetics. The tabular probability level for chi-square was P = 0.50, thus we: a. accept that 3:1 is probably the true ratio b. reject the 3:1 hypothesis c. conclude that Mendel was wrong d. conclude that there must be more than one gene involved e. demand more research dollars to do the experiment over again 53. Fruit color of squash is determined by interacting loci: AA or Aa give white, aaBB or aaBb give yellow, and aabb gives green. What are the phenotypic frequencies of the offspring from a cross between two fully heterozygous plants? a. 9 white : 6 yellow : 1 green b. 9 white : 3 yellow : 4 green c. 10 white : 3 yellow : 3 green d. 12 white : 3 yellow : 1 green e. none of the above 54. An allegation of baby swapping was reported to you, the hospital administrator. Pick out the possible parents of an infant with type AB blood. a. the woman with type O and the man with type A b. the woman with type O and the man with type AB c. the woman with type B and the man with type O d. the woman with type B and the man with type A e. none of the above could be the right parents 55. The concept "one gene:one enzyme" is partially incorrect because: a. some enzymes are oligomeric b. not all genes produce enzymes c. polypeptides are modified to produce enzymes d. all of the above e. none of the above 56. Which statement is true of the double helix? a. GC pairs involve two hydrogen bonds b. purine pairs with purine, and pyrimidine pairs with pyrimidine c. heating causes the strands to separate d. all of the above e. none of the above 57. Green colorblindness is a sex-linked recessive trait. In a family, the older son has normal vision, whereas the younger son is colorblind. One can realistically surmise: a. the father most probably was colorblind b. the father most probably had normal color vision c. the mother most probably was colorblind d. the mother most probably had normal color vision e. it was most probably the milk man 58. A nucleotide substitution may be undetected because: a. the code is ambiguous b. a new amino acid is coded at an unimportant location c. the organism is homozygous d. it involves a frameshift e. none of the above 59. The Hershey-Chase experiment infected bacteria with radioactively labelled phage virus. The experiment proved that DNA, not protein, was the genetic material, because: a. radioactive S was found in the infected bacteria, and radioactive P was found in the phage "ghosts" (the remaining protein coats) b. radioactive P was found in the infected bacteria, and radioactive S was found in the phage "ghosts" (the remaining protein coats) c. both radioactive P and S were found in the infected bacteria d. both radioactive P and S were associated with the phage "ghosts" (the remaining protein coats) e. none of the above 60. 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 61. 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 65 65 30 30 5 5 What is the map distance between A and C? a. 6 map units b. 7 map units c. 13 map units d. 14 map units e. 21 map units 62. What molecule is transcribed from the DNA template, is single stranded, is typically a large molecule, and has a short half-life (high turnover)? a. rRNA b. mRNA c. enzyme d. polypeptide e. polymerase 63. Assume that two genes determine two different traits. Gene A has two alleles, one of which is dominant, and the other recessive. Gene B has two alleles, which are codominant. In a diploid organism, how many possible phenotypes are there? a. 6 b. 8 c. 9 d. 16 e. 27 64. A pregnant hemophilia carrier survives her fall from an airplane, and starts a family on an uninhabited island. (Hemophilia is caused by a recessive, sex-linked allele.) Her nonidentical twin offspring, boy and girl, grow up, mate, and produce a son. What is his chance of having hemophilia? a. 0% b. 25% c. 50% d. 75% e. 100% 65. Darwin's theory of evolution, presented in The origin of species, left what major conceptual gap? a. it could not account for companion species living in different habitats b. it could not account for the origin of domestic breeds c. it could not account for mimicry d. it could not account for the basis of variation e. it could not account for the length of the giraffe's neck Matching (30 pts.) In each of the following twenty-one blank spaces, insert the correct word or phrase from the list at the bottom of the page.
66. "Wobble" in the third nucleotide of tRNA's anticodon is believed to result in inexact complementarity. This permits what key characteristic of the genetic code?
__________________________________. 67. Something which normally regulates cell growth, but can mutate into a cancer-causing trait
__________________________________. 68. A labelled macromolecule, such as DNA, which is used to detect target molecules
__________________________________. 69. A type of protein made of two or more polypeptides
__________________________________. 70. A discredited model for the structure of DNA, based on erroneous data suggesting equal composition of bases A, T, G, and C
__________________________________. 71. A stage of the cell cycle during which DNA synthesis occurs
__________________________________. 72. Base analogs can cause this
__________________________________. 73. Change in shape of the repressor protein, caused by the inducer lactose
__________________________________. 74. In human blood types the alleles coding for the A antigen and the B antigen are related by
__________________________________. 75. An organism lacking a nucleus
__________________________________. 76. All the genes of an organism; also, the allelic condition for a particular gene or genes.
__________________________________. 77. The type of chromosomes which are similar and can pair during meiosis
__________________________________. 78. A type of mutation involving a deletion or an insertion of one or more nucleotides, resulting in a garbled message
__________________________________. 79. The diploid cell from the union of two haploid gametes.
__________________________________. 80. What the "p" term represents in the formula p2 + 2pq + q2
__________________________________. 81. Random loss of alleles due to small population size
__________________________________. 82. The correspondence between the sequence of nucleotides and the sequence of amino acids resulting from translation
__________________________________. 83. A condition giving rise to progeny ratios which would not be predicted on the Mendelian principle of independent assortment of genes during meiosis.
__________________________________. 84. A good measure of dispersion
__________________________________. 85. There is one of these for each chromosome
__________________________________. 86. A method for amplifying DNA segments to large number of copies
__________________________________. 87. The three-nucleotide decoding sequence used by tRNA
__________________________________. 88. A genetic interaction or nonreciprocal masking. For example, the Bombay allele in humans (hh) always leads to type O blood, regardless of the presence of an A or a B allele.
__________________________________. 89. A type of cell division which leads, ultimately, to new genetic combinations
__________________________________. 90. A protein present in the eukaryotic chromosome
__________________________________. 91. A type of individual having three or more complete sets of chromosomes
__________________________________. 92. What results from polygenic inheritance
__________________________________. 93. A form of radiation which is absorbed by DNA, and produces mutations
__________________________________. 94. The place in a protein where structural integrity is required for function; mutations which disrupt the protein here usually result in defective protein
__________________________________. 95. A type of chemical which can serve as an external signal, affecting gene regulation in a different cell or different organ of the same organism
__________________________________. Short answer (25 pts.)
96. List Mendel's four postulates: (4 pts.) a. __________________________________ b. __________________________________ c. __________________________________ d. __________________________________ 97. What is the advantage to an organism in having regulatory genes (15 words or less)? (3 pts.)
98 Draw a picture of a metabolic pathway involving two enzymes: (5 pts.)
99. A plant with genotype AaBb is self-fertilized. A and B are two genes controlling separate traits. Using Punnett's square, show how to find the phenotypic ratio of progeny. (Write the gametes in the rows and columns, place the genotypes in the cells of the table, and show by lines, how you accumulate the plants with identical phenotypes, to find their ratio.) (8 pts.)
The phenotypes and their ratios are: 100. Assume that a serious human disease is discovered to be controlled by a recessive allele. Some, but not all, homozygotes eventually express the disease in early adulthood. It is assumed that environmental factors are involved in whether a person comes down with the disease. How can genetic knowledge be helpful? List three specific strategies for applying genetic knowledge to help people, the genetic basis, who might be helped, as well as any concerns that exist about the reliability of the "help". (You can reuse the same strategy in a different way.) (5 pts.)
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