B250WT2F04 - M .CO 411 MED - PR E OM BIL 250/GU...

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Unformatted text preview: M .CO 411 MED - PR E OM BIL 250/GU “Genetics” 10/19/04 Form 1 - PR EME D41 1.C Exam 2 1.C OM *: The highlighted choice is the correct answer. P - PR EME D41 1. Which of the following is NOT true about homologous chromosomes? D41 1.C OM - PR EME D41 1.C OM a). Homologous chromosomes are identical in length. b). Homologous chromosomes share the same centromere locations. c). One of each pair of homologous chromosomes is produced from the other in S phase. d). Homologous chromosomes carry the same sequence of gene sites (loci). e). One chromosome is of maternal origin while the other is of paternal origin. - PR EME 2. Which of the following is NOT a difference between mitosis and meiosis? - PR EME D41 1.C OM - PR EME D41 1.C OM a). Mitosis begins with a 2n cell while meiosis begins with a 1n cell. b). Mitosis produces two cells while meiosis produces 4 cells. c). Mitosis produces genetically identical cells whereas meiosis produces genetically different cells. d). Mitosis produces either haploid or diploid cells (depending on the original cell) whereas meiosis always produces haploid cells. e). Mitosis occurs in somatic cells while meiosis occurs in germ line cells. 1.C OM 3. If the p53 gene in a cell is mutated, which of the following situations may occur? - PR EME D41 1.C OM - PR EME D41 a). Cells with damaged DNA may proliferate in an uncontrolled manner b). The G0 checkpoint won't work properly c). Cells cannot pass the M checkpoint, no matter what d). Cells cannot pass the G1/S checkpoint e). Cells are marked for apoptosis - PR EME D4 11. COM 4. During metaphase II for an organism with a diploid number of 4, how many chromatids are aligned in the equatorial plane of a cell? - PR EME D4 11. COM a). 2 b). 4 c). 6 d). 8 e). 10 PRE MED 411 .CO MPRE M ED4 11. COM 5. In a healthy female, how many secondary oocytes would be expected to form from 100 primary oocytes? How many first polar bodies? a) 200, 50 b) 100, 50 M .CO 411 MED - PR E - PR EME D41 1.C OM c) 200, 300 d) 100, 100 e) 50, 50 1.C D41 - PR EME 3:1 ; 300 and 100 1:1; 200 and 200 1:2:1; 100, 200, and 100 None of the above. 1.C OM a) b) c) d) OM - PR EME D41 1.C OM 6. Assume that in a series of experiments, plants with round seeds were crossed to plants with wrinkled seeds and the following offspring were obtained: 220 round; 180 wrinkled. What genotypic ratio is expected? Based on the information provided above, what are the expected (theoretical) numbers of progeny of each phenotypic class? - PR EME D41 1.C OM - PR EME D41 7) Dentinogenesis imperfecta is a rare, autosomal, dominantly inherited disease of the teeth which occurs about one in 8000 (Witkop, 1957). The teeth are somewhat brown in color and the crowns wear down rapidly. Assume that a male with dentinogenesis imperfecta and no family history of the disease, marries a woman with normal teeth. What is the probability that their first child will be a girl with dentinogenesis imperfecta? 1.C OM - PR EME D41 1.C OM a) _ b) 1/8 c) _ d) 1/16 e) 0 - PR EME D41 8) Hemizygosity would most likely be associated with which of the following? 11. COM - PR EME D41 1.C OM a) codominance b) incomplete dominance c) trihybrid crosses d) sex-linked inheritance e) sex-limited inheritance COM - PR EME D4 9) Assume that a dihybrid F2 ratio, resulting from epistasis, was 9:3:4. If a double heterozygote was crossed to the fully recessive type, what phenotypic ratio is expected among the offspring? MPRE M ED4 11. COM - PR EME D4 11. a) 1:1:2 b) 9:3:3:1 c) 1:2:1 d) 3:1 e) 9:3:4 PRE MED 411 .CO 10) Two forms of hemophilia are determined by genes on the X chromosome in humans. M .CO 411 MED - PR E OM - PR EME D41 1.C OM Assume that a phenotypically normal woman whose father had hemophilia is married to a normal man. What is the probability that their first child will have hemophilia, if their first child is a boy? What is the probability that their first child will have hemophilia, if their first child is a girl? D41 1.C OM - PR EME D41 1.C a) 1/2; 1/2 b) _ ; 0 c) _ ; 0 d) _; 1/2 e) 0; 0 D41 1.C OM Phenotype wild yellow wild - PR EME Sex male male female - PR EME D41 1.C OM - PR EME 11) In a Drosophila experiment a cross was made between homozygous wild type females and yellow-bodied males. All of the resulting F1's were phenotypically wild type. However, adult flies of the F2 generation (resulting from matings of the F1's) had the following characteristics: Number 123 116 240 D41 1.C OM What is the pattern of inheritance of the mutant gene for yellow body? autosomal dominant autosomal recessive dominant, sex-linked recessive, sex-linked - PR EME D41 1.C OM - PR EME a) b) c) d) - PR EME D4 11. COM - PR EME D4 11. COM - PR EME D41 1.C OM 12) Below is a pedigree of a fairly common human hereditary trait where the boxes represent males and circles, females. Shading symbolizes the abnormal phenotype. PRE MED 411 .CO MPRE M ED4 11. COM Given that one gene pair is involved, determine the inheritance pattern of this gene pair: a) b) c) d) autosomal dominant autosomal recessive dominant, sex-linked recessive, sex-linked M .CO 411 MED - PR E - PR EME D41 1.C OM 13) Regarding the ABO blood group system in humans, if one of the individual’s parents is type AB, yet this individual expresses the O blood type, it is likely that this individual has the ________ genotype. 1.C OM - PR EME D41 1.C OM a) IOIO b) IAIB C) HH d) hh e) Hh - PR EME D41 14) In fruit fly, the genetic basis for determining the sex "male" is accomplished by the presence of ________. - PR EME D41 1.C OM - PR EME D41 1.C OM a) a particular portion of the Y chromosome b) one X chromosome c) a balance between the number of X chromosomes and the number of haploid sets of autosomes d) high levels of estrogen e) multiple alleles scattered throughout the autosomes D41 1.C OM 15) Give the sex of these two organisms. Each has a sex chromosome complement of (XXY), and assuming that the autosomes are present in the normal number. - PR EME Sex Chromosome Complement XXY Organsm Drosophila __?___ 1.C OM Humans ___?__ - PR EME D41 1.C OM - PR EME D41 a) male; male b) female; female c) female; male d) male; female e) metafemale; metafemale - PR EME D4 11. COM 16) How many Barr bodies would one expect to see in cells of 49, XXXXX syndrome females? - PR EME D4 11. COM a) one b) two c) three d) four e) five PRE MED 411 .CO MPRE M ED4 11. COM 17) The Lygaeus mode of sex determination is the a) XY/XX scheme. b) XX/XO scheme. M .CO 411 MED - PR E - PR EME D41 1.C OM c) XO/YY scheme. d) hermaphroditic scheme. e) single translocations in the X chromosome. OM - PR EME D41 1.C OM 18) Assume that a Chi-square test was conducted to test the goodness of fit to a 3:1 phenotypic ratio and a Chi-square test provided a probability value of 0.02. Should the null hypothesis be accepted? How many degrees of freedom would be associated with this test of significance? D41 1.C OM - PR EME D41 1.C a) yes, 2 b) yes, 1 c) no, 1 d) no, 2 e) no, 3 OM - PR EME 19) Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd x AabbCCdd will have the aabbccdd genotype? - PR EME D41 1.C OM - PR EME D41 1.C a) 34 b) 24 c) 1/16 d) 1/64 e) zero - PR EME D41 1.C OM 20) Given below is a hypothetical "wild type" polypeptide containing twelve amino acids (each letter arbitrarily represents one amino acid). Assume that gene X is responsible for its synthesis. OM A-B-C-D-E-F-G-H-I-J-K-L 11. COM O-S-E-Y-I-U-T-S-R-J-K-L A-B-C-D-E-F-G-H-I-J-K-L -L -K-L A-B- - PR EME D4 a) b) c) d) e) - PR EME D4 11. COM - PR EME D41 1.C The amino acid "A" is at the C terminus and amino acid "L" is at the N terminus. Select the sequence of amino acids from gene X under the following circumstances : A nonsense mutation involving bases 7, 8, and 9 in the coding region of the mRNA (counting from the 5' end of the coding region of the mRNA), from the following five choices: PRE MED 411 .CO MPRE M ED4 11. COM 21) A class of mutations which results in multiple contiguous amino acid changes in proteins is likely to be the following: a) base analogue. M .CO 411 MED - PR E OM - PR EME D41 1.C OM b) transversion. c) transition. d) frameshift. e) recombinant. 1.C D41 1.C OM - PR EME D41 a) xeroderma pigmentosum. b) SCID. c) phenylketonuria. d) muscular dystrophy. e) Huntington disease. OM - PR EME D41 1.C 22) Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates. Such individuals are likely to suffer from - PR EME 23) Which of the following is NOT true about sex-linked genes? - PR EME D41 1.C OM - PR EME D41 1.C OM a) In humans, the term sex-linked usually refers to X-linked characters. b) Fathers pass X-linked alleles to all their daughters, but not sons. c) Mothers can pass sex-linked alleles to both sons and daughters. d) Far more males than females have disorders that are inherited as sex-linked recessives. e). All statements above are true. OM 24) Mutations which arise in nature, from no particular artificial agent are called - PR EME D41 1.C OM - PR EME D41 1.C a) natural mutations. b) induced mutations. c) spontaneous mutations. d) chromosomal aberrations. e) cosmic mutations. - PR EME D4 11. COM 25) Purines and pyrimidines found in DNA could exit in tautomeric forms, each differing by only a single proton shift in the molecule. Such tautomeric shifts could result in mutation through the formation of anomalous pairs, such as: MPRE M ED4 11. COM - PR EME D4 11. COM a) A= G and T = C pairs b) A = T and G = C pairs c) A = A and T = T pairs d) A = C and G = T pairs e) G = G and C = C PRE MED 411 .CO Extra credit questions (10 points each): M .CO 411 MED - PR E OM OM - PR EME D41 1.C 26) LeMaire-Adkins et al’s paper “Lack of checkpoint control at the metaphase/anaphase transition : ….” published in “Journal of Cell Biology” concerns - PR EME D41 1.C OM - PR EME D41 1.C a) a mechanism of checkpoint control during mitosis in mammalian females. b) a mechanism of mitotic disjunction in mammalian females. c) a mechanism of mitotic nondisjunction in mammalian females. d) a mechanism of meiotic disjunction in mammalian females. e) a mechanism of meiotic nondisjunction in mammalian females. D41 1.C OM 27) The article “How cells get the right chromosomes” published in “Science” by Bruce Nicklas discovered that PRE MED 411 .CO MPRE M ED4 11. COM - PR EME D4 11. COM - PR EME D4 11. COM - PR EME D41 1.C OM - PR EME D41 1.C OM - PR EME D41 1.C OM - PR EME D41 1.C OM - PR EME a) when cell divide, the daughter cells will always get the right chromosomes. b) chance events are not involved in chromosome delivery. c) errors in chromosome delivery are avoided by diverse uses of DNA restriction enzymes during the mitotic process. d) errors in chromosome delivery are avoided by diverse uses of mechanical tension from the mitotic process. e) errors in chromosome delivery are avoided by diverse uses of DNA repair mechanisms during the mitotic process. M .CO 411 MED - PR E OM Short answer format (each question is worth 10 points): - PR EME D41 1.C II. - PR EME D41 1.C OM - PR EME D41 1.C OM 1) Dosage compensation in mammals typically involves the random inactivation of one of the two X chromosomes relatively early in development. Such X-chromosome inactivation often leads to phenotypic mosaicism. Assume that black fur in cats is due to the X-linked recessive gene b while its dominant allele B produces yellow fur. A Bb heterozygote is a mosaic called "tortoise shell" or "calico." Using appropriate gene symbols, diagram a mating between a black male and a "calico" female. Give the sex, phenotypes and genotypes of all the offspring. 1.C OM Answer: bY x Bb = - PR EME D41 Bb (calico female), bb (black female), BY (yellow male), bY (black male) - PR EME D41 1.C OM 2) Assume that a cross is made between a heterozygous tall pea plant and a homozygous short pea plant. Fifty offspring are produced in the following frequency: D41 1.C OM 30 = tall 20 = short - PR EME (a) What frequency of tall and short plants is expected? - PR EME D41 1.C OM (b) If one wanted to test the goodness of fit between the observed and expected values, provide a statement of the null hypothesis. D41 1.C OM (c) Compute a Chi-square value associated with the appropriate test of significance. _2 = ∑ (o – e)2/ e (d) How many degrees of freedom are associated with this test of significance? - PR EME D4 11. COM - PR EME Answer: (a) 1:1 (25 tall and 25 short) (b) The deviations from a 1:1 ratio (25 tall and 25 short) are due to chance. (c) _2 = 2 (d) 1 COM - PR EME D4 11. COM 3) Cystic fibrosis is an autosomal recessive disorder. A male whose brother has the disease has children with a female whose sister has the disease. It is not known if either the male or the female is a carrier. If the male and female have one child, what is the probability that the child will have cystic fibrosis? PRE MED 411 .CO MPRE M ED4 11. Answer: 2/3 X 2/3 X 1/4 = 1/9 M .CO 411 MED - PR E 1.C OM - PR EME D41 1.C OM - PR EME D41 1.C OM 4) A color-blind woman with Turner syndrome (XO) has a father who is color blind. Given that the gene for the color blind condition is recessive and X-linked, provide a likely explanation for the origin of the color blind and cytogenetic conditions in the woman. Answer: The woman inherited an Xrg chromosome from the father. Nondisjunction in the female (either at meiosis I or II) produced an egg with no X chromosome, which, when fertilized by the Xrg-bearing sperm produced the Turner syndrome condition. D41 1.C OM - PR EME D41 5) Differentiate between point mutations that are transitions and those that are transversions. Using the DNA bases (A, T, G, and C), list two types of transitions and two types of transversions. Can transitional mutations and transvertional mutations cause frameshift mutations? - PR EME D41 1.C OM - PR EME Answer: Transitions involve pyrimidine - pyrimidine and purine purine substitutions while transversions involve pyrimidine purine and purine pyrimidine substitutions. If they can pick any two of the following four types of transitions and eight types of transversions, they can get the full credit on this point. A;T- 1.C G; G C; C - T - PR EME D41 A- OM Four types of transitions: OM Eight types of transversions: 1.C OM - PR EME D41 1.C A -> T, C G -> T, C T -> G, A C -> G, A PRE MED 411 .CO MPRE M ED4 11. COM - PR EME D4 11. COM - PR EME D4 11. COM - PR EME D41 The second part of the question: Neither transitional or transversitional mutations can cause frameshift mutations. ...
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This document was uploaded on 10/27/2011 for the course BIL 250 at University of Miami.

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