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Fall04Examwith+key

Fall04Examwith+key - its 7 Name EXAM#IA i’rinciples of...

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Unformatted text preview: its 7 Name: EXAM #IA i’rinciples of Genetics (Biol 2153), Larkin, Sec. 5-8 Fall 2004 Remember to fill in your name and ID number on the answer sheet! Choose the best answer for each question by filling in the appropriate space on your answer sheet. There are 33 questious. 1. Which of the following most directly controls an organism’s phenotype: a) transcription. 13 translation rotein function. mutation. e) replication. 2. Who 'rst realized that blending inheritance was not compatible with evolution by natural selection? 93“ Charles Darwin. ' 5) Walter Sutton. c) Calvin Bridges. d) Theodor Boveri. e) Gregor Mendel. 3. The haploid number of chromosomes in humans is 23. How many chromosomes and chromatids are present in a secondary oocyte? a 23 chromosomes, 23 chromatids 23 chromosomes, 46 chromatids c 46 chromosomes, 46 chromatids d) 46 chromosomes, 92 chromatids e) 92 chromosomes, 92 chromatids 4. In a diploid organism, what stage of the mitotic cell cycie has the same number of chromosomes as a gamete? a) GI b) S c) G2 metaphase a: one of the above 5. M_n__,__.u_ S phase occur during meiosis? é’Before prophase I 13) During prophase I c) During anaphasei (1) Before prophase 11 e) In gametes Name: Questions 6 through 9 refer to the following cross involving the independently asserting genes A, B, C, D, E, and F. Unless otherwise stated, assume that the capitalized allele is fully dominant, and that these enes shew no genetic interactions (epistasis, etc.) In t 1/L A; l ! AaBBchdeeff X AabchDdEEFF (3/ \/ 1 l '7. 1 l l \ f 5 I 6. How many different types of gametes can the parent on the right produce? L a) 2 ($4 t _ 8 . f l 1 16 “s L 1 e) 32 7. How any different phenotypes can be produced from this cross? ,. -. 8 g 18 c) 32 d) 72 e) 128 8. What proportion of individuals having the dominant phenotype for all six genes will be produced from this cross? a) 3/4 b 9/ 16 @5982 3/ 16 e) 0 9. If gene A is incompletely dominant, how many phenotypes can be produced by this cross? a) 6 b 8 @12 18 e) 32 10. In the plant morning glory, a gene for flower color (C I'm colored, c = white, C is dominant) asserts independently from a gene for leaf color (Y = green leaves, y 2 yellow leaves, Y is dominant). The following results were obtained from a cross: 24 colored flowers, green leaves 26 colored flowers, yellow leaves 23 white flowers, green leaves 27 white flowers, yellow leaves What were the genotypes of the parents? fie Yy x cc Yy c Yy x cc yy c) Cc Yy x Cc yy (1) Ce Yy x Cc Yy Name: ll. In horses, there are three coat color patterns, termed cremello (beige), chestnut (brown), and palomino (golden). A horse breeder keeps records for many years, and gets the following results for the offspring of palomino x palomino crosses: 500 cremello, 475 chestnut, 1025 palomino. Are these results consistent with a ratio of 4 cremello: 3 chestnut: 9 palomino? a) 952:2 1.9, results consistent with 4:3:9. b) x2m 8.9, results consistent with 4:3:9. ngZ-z: 21.1, results not consistent with 4:329. (W: 35.6., results not consistent with 4:3:9. 12. Palomino horses never breed true when crossed with other palominos, while cremello and chestnut horses always breed true. Which of the following is the hemst explanation for these results and the results in the previous question? a) Two genes, and cremello is epistatic to chestnut. b The palomino allele is lethal when homozygous. cremello and chestnut are incompletely dominant alleles of one gene, palominos are heterozygous. . d) cremello, chestnut, and palomino are three alleles of a single gene. 13. You discover two true—breeding varieties of a butterfly, red and yellow. You cross a red butterfly with a yellow butterfly, and the F1 butterflies are all red. When an F 1 butterfly is crossed with a yellow butterfly, 4 distinct phenotypic classes of colored butterflies are detected, each with a frequency of 1/4. Assuming that . there is simple dominance, independent assortment, and there are no unusual genetic interactions, how many genes are likely to be involved? ed Qt d4 e)5 14. What is the most probable genotype for the true—breeding yellow butterfly? a Homozygous dominant for all genes. Homozygous recessive for all genes. 0 Heterozygous for all genes. 15. If you wanted to use a x2 test to test the hypothesis that each of the phenotypic classes in Q. 13 were a good fit t a 1/4 ratio, how many degrees of freedom would there be? a) @t c) 7 d) 8 e) 15 - _ Name: 16. The I gene involved in ABO blood type encodes a glycos l transferase enzyme that modifies the polysaccharide chains found on cellular glycoproteins. The I allele adds the monosaccharide N—acetyl- galactosamine, the 1‘3 allele adds the monosaccharide galactose, and the IQ allele is defective, and cannot add any monosacchaiide. On an island in the South Pacific, you discover a new allele of I that causes the glycosyl transferase to add the monosaccharide xylose instead. This new allele is probably a new mutation changing the function of the enzyme. This new allele is a/an: a) amorphie allele. b) hypomorphic allele. hypennorphic allele. neoniorphic allele. Questions 17 and 18 re‘léer to the following four pedigrees. Filled circles=affected individuals. l7. Which of these pedigrees is the only one in Which the affected trait must be recessive? b 18. Which of these pedigrees is the only one in which the affected trait could be X-linked and recessive? C, 19. My father, my brother and l have high cholesterol, and this is probably due to an inherited tendency to high cholesterol. My father had a heart attack when he was younger than I am now. Hewever, I have controlled my cholesterol level by diet and medication, and my doctor says that I are less likely to have a heart at it than my father was. Which of the following best describes this situation? "a An environmental effect on a phenotype. b) Incomplete penetrance . 0) Variable expressivity. d) Incomplete dominance. Name: 20. Tay~Sachs disease is a’recessive autosomal disease resulting from a defect in lipid metabolism that causes blindness, paralysis, and early death. A woman whose parents are unaffected has an affected brother. What is the chance that she is a carrier? a) 1/4 b) 1/3 c_ 1/2 21. Tay~Sachs disease is very common among Jewish populations of Northern European ancestry. In this group, approximately 1/50 individuals is a carrier. If the woman from the previous question marries a Jewish man of Northern European ancestry, what is the chance that they will have an affected child? 1/300 22. Four different recessive mutations (a, b, c and d) are found that result in professors who mumble, in ‘ contrast to normal professors, who are easy to hear. To determine whether these mutations represent mutations in the same gene or genes, you perform all possible crosses between mumbling professors, with the following results: aaxbbm Fl mumble our to. same as 2: cc: F1 all normal C; an x dd: Fl all normal bb x cc: F1 all normal (3 bb x dd: Fl all normal cc x dd: F1 all normal How many different genes are represented by these mutations? a) l b) 2 c 3 4 Name: 23. In Labrador retrievers, the synthesis of coat pigments occurs by the following pathway: Y Yellow-~~~~m—> Chocolate ————mm> Black Y and C are enzymes are catalyzing the reactions converting one pigment into another. They are encoded by genes also named Y and C. Assume that both genes show simple dominance and assert independently. What ratios of types of offspring would be produced from the cross Yy Cc x Yy Cc? ...,\ 1/2 black, 1/4 chocolate, 1/4 yellow / 16 black, 3/ 16 chocolate, 4/16 yellow c 9/16 black, 3/16 yellow, 4/ 16 chocolate d) 9/ 16 black, 7/16 chocolate e) 9/16 black, 7/16 yellow 24. A yellow Labrador (like previous question) that is known to be of the genotype yy cc is crossed with a black Labrador of unknown genotype. The offspring are 1/2 yellow and 1/2 black. What is the genotype of the black Labrador? a) YYCC YYCC yCC yyCC e) Ych pistasis u codominance c) incomplete dominance d) linkage ‘ e) sex determination 25. T‘e of genetic interaction involved in the previous two questions is called: 26. A wealthy man with blood-type AB dies, and leaves his entire fortune of $10,000,000 to be divided between his only living heirs, two long-dost sons born to different mothers of unknown blood—type. Three men turn'up and try to claim the fortune, one of blood~type A, one of blood-type B, and one of blood-type 0. Which of these men must be an impostor, based on blood-type a) A b B O _ Can’t be sure which is the impostor. Name: 27. The spindle is a structure found during which of the following stages of the mitotic and meiotic cell cycle? a) metaphase of mitosis. b) metaphase I of meiosis. c metaphase ll of meiosis. d) l of the above. none of the above. 28. Which of the following is not true of the Y chromosome? a) Its terminal regions are similar to those of the X chromosome. b It is morphologically distinct from the X chromosome. c It has more genes than the X chromosome. All of the above are true of the Y e) None of the above are true of the Y 29. What was the most important scientific conclusion to come from the discovery of sexulinkage of the w gene i as osophila‘? Genes are on chromosomes. '0 Sex is determined by chromosomes. c) Blending inheritance is false. (1) Dominance was explained. 0 blood has children with a woman who has normal vision and olorblind. Colorblindness is determined by an X~linked gene, e couple will (have a child (of either sex) who is L a 11g V K 6) 3/16 30. A man who is colorblind and has type type AB‘blood. The woman’s father was c and blood type is autosomal. What is the chance that th colorblind and has type A blood? 31. A woman is born affected b family‘l... @l er father was affected. -' Her mother was homozygous for the disease allele. c) Nondisjunction occurred during oogenesis in her mother. a - (D d) All of her sisters will also be affected. Name: 32. In a particular plant, there are four flower colors, maroon, orange, gold and yellow. From crosses among various plants, some known to be true-breeding, and some unknown whether they are truewbreedjng, you obtain the following results: trueubreeding maroon x true-breeding orange —-> all maroon. true—breeding maroon 2; tale—breeding yellow ..__> all maroon. unknown maroon 3; true—breeding orange -——> 1/2 maroon, 1/2 orange. unknown gold x unknown gold—*9 1/2 gold, 1/4 orange, 1/4 yellow. ammown maroon 1-: unknown gold—~> 1/2 maroon, 1/4 orange, 1/4 gold. No true~breeding gold lines are known. What is 1* best explanation of these results? Q hree alleles of a single gene. b Four alleles of a single gene. 0) Two genes producing four phenotypes. d) Epistatis between two genes. 33. Based on the results in the previous question, what would you expect for a cross of true—breeding orange x truembreeding yellow? All gold. ) All orange. c) All yellow. d) All maroon. e) 1/2 gold, 1/2 yellow. TABLE 3.2 Table of Chi-Square (X21593 Critical Vaiucs“ Degrees of Freedom 5% Critical Vafue 1 3.841 , ' __ -. . . . 2 - ‘ 5.991 1: -. ,1" f , -- 3 7.815 ‘ ‘-'“""""-,‘=_'V' Sign. 4 9.488 . ‘ . ' 5 11.070 - ' 6 12.592 '7 V 14.067 . ‘ _ - . ‘8" " ' <15.507._. .' ' ' 9 16.919 . ' ' 10 18.307 15 24.996 ' ‘ ' - ‘ 20 31.410 "__ 25 37.652 ' " _- .‘ I ' 30 43.773 . ' 7 - “Seiected efitries from R. A. Fisher and Yates, “i943, Statisficnl Tables '2_ 5' it? ' for qufogiml, Agricultural and Mvdfml Rearmtch. Oliver and Boyd, '. London. ‘ ...
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