AGR 3303 - Genetics

16 or 19 Dec 1996

University of Florida - Fort Lauderdale

Final exam

Instructions, important!

Part I. (126 pts.)

Set A1: Multiple choice set

1. natural selection
2. hereditary variation
3. survival of the fittest
4. reproductive fitness
5. breeds of domestic animals

2. Philip Busey's main criticism of associating intelligence and race is:

1. it's not nice
2. behavior is too complex a trait to be caused by genes
3. intelligence is too hard to define
4. we're all descended from the same source
5. there is no genetic variation among humans

3. The emergence of modern genetics required:

1. reductionism, breaking things down
2. the human genome project
3. freedom from religion
4. discovery of DNA
5. knowledge of evolution

4. An organelle which is believed to be an endosymbiont:

1. endoplasmic reticulum
2. mitochondrion
3. centromere
4. chromosome
5. ribosome

5. What was the main reason for Mendel's ability to discover unit factors of inheritance?

1. his ability to make hybrids
2. grant support
3. disbelief in the fixity of species
4. careful cataloging of observations
5. Darwin's discovery of evolution

6. The characteristics of the hereditary material are:

1. pangenesis, spontaneous creation, inheritance of acquired characteristics, and special creation
2. replication, transcription, translation, and recombination
3. replication, mutation, expression, and storage
4. all of the above
5. none of the above

7. DNA was proven to be the hereditary material in 1944, but this was generally ignored until 1953 because:

1. the work was written in an obscure Austrian journal
2. the Central Dogma was not discovered until 1953
3. the early work was done on prokaryotes
4. all of the above
5. none of the above

9. Draw a plant cell and label at least its components. Make sure that anything having to do with genetics is drawn and labeled. (7 pts.)

Set B1: Multiple choice set

1. during meiosis there will be 12 chromosomes going to each pole
2. during meiosis, there will be 12 pairs of chromosomes
3. during mitosis there will be 6 chromosomes going to each pole
4. during mitosis there will be 12 chromosomes going to each pole
5. during mitosis there will be 24 chromosomes going to each pole

11. In contrast to mitosis, in meiosis there is/are:

1. nonidentical daughter cells
2. longitudinal division
3. two daughter cells
4. all of the above
5. none of the above

12. DNA replication occurs during:

1. mitosis
2. meiosis
3. interphase
4. all of the above
5. none of the above

13. What is true for human sex chromosomes?

1. the man always inherits his X from his father's mother
2. the woman always inherits her X from her father's mother
3. the man always inherits his Y from his father's mother
4. the woman always inherits her Y from her father's father
5. the man always inherits his X from his mother's father

14. Down syndrome in human is caused by:

1. an extra sex chromosome
2. an extra autosome
3. a missing autosome
4. polyploidy
5. none of the above

15. Which, if any, of Mendel's postulates is violated by the relationship of genes on chromosomes:

1. unit factors in pairs
2. dominance / recessiveness
3. segregation
4. independent assortment
5. none of the above

16. How many different chromosome configurations are possible in the gamete following meiosis if there are three pairs of chromosomes? (To visualize the problem, it might help to symbolize the chromosomes A1, A2, B1, B2, C1, C2; A1, B1, and C1 are from one parent, and A2, B2, and C2 are from the other parent.)

1. 2
2. 3
3. 4
4. 8
5. 9

18. Explain the important differences between meiosis and mitosis. Make sure to explain the genetic characteristics of daughter cells and their chromosomes. A table is provided. (7 pts.)

Characteristic	Meiosis	Mitosis

Set C1: Multiple choice set

1. The woman with type A blood could not be the mother.
2. The woman with type O blood could not be the mother.
3. The woman with type B blood could not be the mother.
4. The woman with type AB blood could not be the mother.
5. Any of the four women could be the mother

21. A woman discovers that her son has Duchenne muscular dystrophy, a progressive muscle wasting caused by a recessive sex-linked allele. What is the chance that her next son will have the disease?

1. 0%
2. 25%
3. 50%
4. 75%
5. cannot be determined without knowing the father's genotype

22. Coat color of mice is determined by interacting loci: bb gives albino, A_B_ gives agouti (an alternately light and dark combination), and aaB_ gives black. What are the phenotypic frequencies of the offspring from a cross between two heterozygous agouti mice (AaBb)?

1. 15 agouti : 1 albino
2. 9 agouti: 3 black : 4 albino
3. 9 agouti : 4 black : 3 albino
4. 12 agouti : 3 black : 1 albino
5. none of the above

23. A crossing experiment results in a phenotypic ratio of 9:3:3:1. The simplest explanation that could adequately explain this result is:

1. There are three genes with linkage
2. There are two genes, each gene with a dominant allele and a recessive allele, and at least one gene is linked
3. There are two genes, each gene with a dominant allele and a recessive allele
4. There is one gene with two alleles
5. None of the above

24. Thalassemia is an inherited anemia controlled by a single allele. Homozygous persons have Thalassemia major, which is almost always fatal in childhood. Heterozygous persons have Thalassemia minor, and are mildly affected. An infant has Thalassemia major. What is the likelihood that a subsequent child of the same parents will have Thalassemia major?

1. 0%
2. 25%
3. 50%
4. 75%
5. 100%

25. A white-flowered plant is crossed with a red-flowered plant. The progeny segregate in the ratio 50% white and 50% pink. This is an example of:

1. polygenes
2. codominance
3. epistasis
4. incomplete dominance
5. pleiotropy

26. Hemophilia is a sex-linked trait which appeared in the male descendants of Queen Victoria of Great Britain. The hemophilia allele is recessive. What proportion of her daughters' sons should be hemophiliac?

1. 0%
2. 12.5%
3. 25%
4. 50%
5. none of the above

Set D1: Multiple choice set

1. the null hypothesis cannot be accepted
2. Mendelian genetics adequately explains the results
3. the genes are not assorting independently
4. the genes must be linked
5. none of the above

29. Five individuals of a bisexual species (e.g., a plant capable of either self- or cross-fertilization) establish a colony on a remote island. One of the original individuals is homozygous recessive for white flowers. The remaining four individuals are homozygous dominant, thus they have purple flowers. After several generations the island is visited by a botanist, who notices individuals with purple flowers and individuals with white flowers. Assuming Hardy-Weinberg equilibrium and no change in the frequency of alleles since the original establishers, what frequency of white flowers does the botanist notice?

1. 1%
2. 2%
3. 4%
4. 8%
5. 10 %

30. Individuals in a population of organisms differ from one another, due to both genotypic and environmental causes. Because it is difficult to assign those differences to the effect of any individual gene, scientists study such populations by a measure of dispersion called:

1. chi-square
2. null hypothesis
3. the range
4. the mean
5. the variance

31. Assume that a single gene has three alleles. In a diploid organism, how many possible genotypes are there?

1. 8
2. 9
3. 16
4. 27
5. 81

32. In contrast to Mendel's categorical approach to studying genetic variability, the variance is used in certain situations because:

1. phenotypic variance can be partitioned into genetic, environmental, and genetic X environmental sources
2. with polygenes, the effect of an individual gene cannot be separately distinguished
3. variance is a measure of dispersion which can be modeled in an additive manner
4. all of the above
5. none of the above

33. Assuming that a population of people is in Hardy-Weinberg equilibrium, and their frequency of sickle cell individuals (homozygous recessives) is about 1 in 600. The frequency of heterozygous carriers must be:

1. about 1 in 600
2. about 1 in 60
3. about 1 in 25
4. about 1 in 12
5. about 1 in 6

34. Jacob is considering a pastoral management contract with Laban, his father-in-law. According to their draft agreement, Jacob will keep, as his payment for goatherding, any ensuing speckled goats from Laban's flock. Laban will retain all the pure black ones. The two flocks will not be allowed to interbreed. Black coat color in goats is controlled by the dominant allele B, while the homozygous recessive (bb) is speckled. Given that all of Laban's goats are black, what is the maximum percent of speckled goats that Jacob can expect to remove from Laban's flock in a single generation?

1. 0%
2. 25%
3. 50%
4. 75%
5. 100%

Set E1: Multiple choice set

1. that DNA is the hereditary molecule
2. the Central Dogma
3. the genetic code
4. the double-helix model of DNA
5. the polymerase chain reaction

38. Which of the following is a nucleotide of DNA:

1. deoxyribose + guanine
2. deoxyribose + nitrogenous base
3. deoxyribose + uracil + phosphate group
4. ribose + pyrimidine + phosphate group
5. none of the above

39. The bacteria of Avery et al. (1944) were transformed by a substance which was inactivated by:

1. RNase
2. proteinase
3. 32P
4. 35S
5. none of the above

40. PCR (the polymerase chain reaction)

1. is a method for cutting DNA
2. is a method for studying the size of polymer chains
3. is a method for amplifying DNA
4. is a method for fractionating DNA
5. is a method for radioactively labeling DNA

41. The UV absorbance spectrum provides circumstantial proof that DNA is the hereditary material, because:

1. the UV absorbance spectrum for DNA is the same as protein
2. the UV absorbance spectrum is the same as the mutation spectrum
3. the UV absorbance spectrum of DNA is the same as mRNA
4. the UV absorbance spectrum is consistent with the tetranucleotide hypothesis
5. the UV absorbance spectrum proves that DNA is a crystalline structure

42. The Hershey-Chase experiment infected bacteria with radioactively labeled phage

1. radioactive S was found in the infected bacteria, and radioactive P was found in the phage "ghosts" (the remaining protein coats)
2. both radioactive P and S were associated with the phage "ghosts" (the remaining protein coats) virus, proving that DNA, not protein, was the genetic material, because:
3. radioactive P was found in the infected bacteria, and radioactive S was found in the phage "ghosts" (the remaining protein coats)
4. both radioactive P and S were found in the infected bacteria
5. none of the above

43. Human insulin can be produced by bacteria, using human DNA. This proves that:

1. the genetic code is a heteropolymer specifying a single amino acid
2. a new amino acid is transcribed from a nonsense mutation
3. avirulent bacteria can be rendered infectious with exogenous DNA
4. bacteria and humans must have similar coding dictionaries
5. translation requires oligomeric proteins homologous to ribosomal tRNA

45. Explain the genetic code, explain its purpose, and list its major language characteristics. Make sure to mention and explain nonsense mutations, frameshift, polypeptides, stop codons, redundancy, tRNA, universality, the locations of the codons and the anticodons, etc. (12 pts.)

Set F1: Multiple choice set

1. the genotype must be heterozygous
2. the altered triplet codon must be redundant
3. the enzyme must be monomeric
4. the gene must be turned on
5. none of the above

47. In the lac operon:

1. posttranscriptional control reduces unnecessary enzyme production
2. when there is lactose present, the structural genes are transcribed
3. lactose represses the transcription of structural genes
4. lactose enables the repressor to bind to the operator region
5. there is a regulatory cascade regulated by hormones

48. The most likely explanation for the relationship between radiation and cancer is:

1. radiation leads to nucleotide substitution(s), which result in the wrong amino acid(s) in the active site of enzymes
2. genes regulating cell division are rendered ineffective
3. most proteins are oligomers
4. all of the above
5. none of the above

49. A cell-free synthesizing system was used to translate the genetic code, using artificial RNA templates. RNA sequences in these templates were matched to amino acid(s), based on the retention of radioactively labeled amino acid. Which concept(s) would be reasonably help the deciphering effort.

1. RNA homopolymers should code for more than one amino acid
2. RNA heteropolymers could code for only one amino acid
3. the ratio of nucleotides predicts the ratio of amino acids
4. all of the above
5. none of the above

50. A short-lived molecule that moves from the nucleus to the cytoplasm is:

1. nucleosome
2. tRNA
3. mRNA
4. polymerase
5. aminoacyl transferase

51. A gene has both a normal form and an abnormal form. The abnormal form of the gene produces an abnormal polypeptide, which disables the function of the resulting monomeric enzyme. Why would heterozygotes (individuals with a normal copy and an abnormal copy of the gene) be functionally normal?

1. because of diffusible substances
2. because of the limited correction due to frameshift mutations
3. because enzymes can be effective in partial amounts
4. because normal polypeptides would join together 25% of the time
5. none of the above

52. Mutations that create structural defects in the oligomeric protein collagen:

1. are recessive
2. are dominant
3. are not expressed
4. all of the above
5. none of the above

__________________________________.

56. The ratio of genotypic variance divided by phenotypic variance

__________________________________.

57. "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?

__________________________________.

58. A labeled macromolecule, such as DNA, which is used to detect target molecules

__________________________________.

59. The place in a protein where structural integrity is required for function; mutations which disrupt the protein here usually result in defective protein

__________________________________.

60. A type of mutation involving a deletion or an insertion of one or more nucleotides, resulting in a garbled message

__________________________________.

61. The correspondence between the sequence of nucleotides and the sequence of amino acids resulting from translation

__________________________________.

62. Homologous ("similar") chromosomes do this, only in meiosis:

__________________________________.

63. What results from polygenic inheritance

__________________________________.

64. This condition is the only human autosomal trisomic in which most individuals survive to adulthood:

__________________________________.

65. A form of a gene:

__________________________________.

66. A type of protein made of two or more polypeptides

__________________________________.

67. A protein present in the eukaryotic chromosome

__________________________________.

68. A haploid cell resulting from meiosis, and which can undergo fertilization, is a:

__________________________________.

69. Recessive alleles are expressed only when they are in this condition:

__________________________________.

70. If the chromosome number is not an exact multiple of the haploid set, the individual is considered to be:

________________________________________.

71. When genes interact in a nonreciprocal manner, this is called:

__________________________________.

72. DNA synthesis occurs during which stage of the cell cycle?

__________________________________.

73. There is one of these for each chromosome:

__________________________________.

74 A cutter enzyme

__________________________________.

75. A method for amplifying DNA segments to large number of copies

__________________________________.

76. The three-nucleotide decoding sequence used by tRNA

__________________________________.

77. The consequence of breeding in small populations

__________________________________.

78. A condition in which the genotypes can be predicted according to (p+q)2

__________________________________.