Multiple Choice (3.35 each) Total = 100pts. Choice the choice that best answers the question! Good luck!

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1 NAME DATE Multiple Choice (3.35 each) Total = 100pts. Choice the choice that best answers the question! Good luck! 1. Could the characteristic followed in the pedigree be caused by an autosomal dominant disease? Why or why not? I II III a. Yes, all individuals fit the autosomal dominant inheritance pattern. b. No, the offspring of I-1 and I-2 contradict an autosomal dominant inheritance. c. No, the offspring of I-3 and I-4 contradict an autosomal dominant inheritance. d. No, the offspring of II-3 and II-4 contradict an autosomal dominant inheritance. e. Yes, the offspring of I-1 and I-2 are consistent with an autosomal dominant inheritance pattern. 2. Round seeds (R) is dominant to wrinkled seeds (r), and yellow seeds (Y) is dominant to green seeds (y). A plant of unknown genotype is testcrossed to a true-breeding plant with wrinkled and green seeds. The offspring produced were 53 round and yellow, 49 round and green, 44 wrinkled and yellow, 51 wrinkled and green. What is the likely genotype of the parent in question? a. RRYY b. RrYY c. RRYy d. RrYy e. rryy 3. Hair color is determined in Labrador retrievers by alleles at the B and E loci. A dominant allele B encodes black pigment, whereas a recessive allele b encodes brown pigment. Alleles at a second locus affect the deposition of the pigment in the shaft of the hair; dominant allele E allows dark pigment (black or brown) to be deposited, whereas recessive allele e prevents the deposition of dark pigment, causing the hair to be yellow. A black female Labrador retriever was mated with a yellow male. Half of the puppies were black and half were yellow. If the genotype of the black female parent was Bb Ee, then what was the genotype of the other parent? a. bb ee b. bb EE c. Bb ee d. BB ee e. BB EE 1

2 4. Which of the following statements about meiosis is false? a. Homologous chromosomes separate from each other during anaphase I. b. Sister chromatids separate from each other during anaphase II. c. Crossing over takes place during prophase I. d. DNA replication occurs between the first and second divisions. e. The chromosome number is reduced by one-half at the end of the first division. 5. A dog has a diploid chromosome number of 78. How many separate DNA molecules should be present at metaphase of mitosis? a. 39 b. 78 c. 156 d. 4 e. None of the above answers is correct. 6. In Labrador retrievers, black coat color is dominant to brown. Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown. What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.) a. The genotype must be BB. b. The genotype must be bb. c. The genotype must be Bb. d. The genotype could be either BB or Bb. e. The genotype cannot be determined from these data. 7. Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. The man has fathered a child with a woman that does not have freckles. What is the probability that their child has freckles? a. 1/4 b. 1/3 c. 1/2 d. 2/3 e. 3/4

3 8. Suppose that the fabulous phenotype is controlled by two genes, A and B, as shown in the diagram below. Allele A produces enough enzyme 1 to convert plain to smashing. Allele a produces no enzyme 1. Allele B produces enough enzyme 2 to convert smashing to fabulous. Allele b produces no enzyme 2. The A and B genes are both autosomal and assort independently. Plain Smashing Fabulous What will be the phenotype(s) of the F 1 offspring of a true-breeding fabulous father and a truebreeding plain mother (aa bb)? a. All plain b. All smashing c. All fabulous d. Plain females and fabulous males e. Fabulous females and smashing males 9. Which of the following statements is true? a. The genotype is the physical appearance of a trait. b. Alleles, genes, and loci are different names for the same thing. c. The phenotype of a dominant allele is never seen in the F 1 progeny of a monohybrid cross. d. A testcross can be used to determine whether an individual is homozygous or heterozygous for a dominant allele. e. All of these statements are true. 10. Joan is phenotypically normal but had a child with the autosomal recessive disease cystic fibrosis (CF) from a previous marriage. Joan s father has hemophila A, a sex-linked recessive condition where the blood fails to clot properly. Her father has survived due to recent treatment advances. Joan now intends to marry Bill, who is also phenotypically normal but who has a sister, Jill, with CF. Bill s parents are phenotypically normal, and there is no history of hemophilia A in his family. Assume that Joan and Bill do marry and have a child. What is the probability that this child will have CF, but will not have hemophilia A? (Hint: This problem requires that you utilize concepts from Chapter 3 as well as Chapter 4.) a. 1/8 b. 1/12 c. 1/24 d. 3/32 e. 5/32 Enzyme 1 Enzyme Interactions among the human ABO blood group alleles involve and. a. codominance; complete dominance b. codominance; incomplete dominance c. complete dominance; incomplete dominance d. epistasis; complementation e. continuous variation; environmental variation

4 12. In the endangered African watchamakallit, the offspring of a true-breeding black parent and a truebreeding white parent are all gray. When the gray offspring are crossed among themselves, their offspring occur in a ratio of 1 black:2 gray:1 white. Upon close examination of the coats, each hair of a gray animal is gray. What is the mode of inheritance? a. One gene pair with black dominant to white b. One gene pair with codominance c. One gene pair with incomplete dominance d. Two gene pairs with recessive epistasis e. Two gene pairs with duplicate genes 13. What is the expected outcome for a human embryo with the XXXY chromosome constitution? a. It would likely develop into a female who will not respond to the hormone testosterone. b. It would likely develop into a sterile male with reduced testes. c. It will always abort early in development before birth. d. It would likely develop into a tall female who may be slightly cognitively impaired. e. It would likely develop into a fertile man with a completely normal male phenotype. 14. In a cell with four chromosomes in its gametes, how many different combinations of chromosomes in the gametes can occur? a. 2 b. 4 c. 8 d. 16 e From the following cross involving four genes, Aa;BB;Cc;Dd x Aa;Bb;Cc;DD, what is the probability of obtaining homozygous dominant genotypes for each gene? a. 1/4 b. 1/16 c. 1/32 d. 1/64 e. 1/ From the following cross involving four genes, Aa;BB;Cc;Dd x Aa;Bb;Cc;DD, what is the probability of obtaining AaBBCcDd, AaBbCcDd, or aabbccdd? a. 1/3 b. 1/16 c. 9/64 d. 27/256 e. 81/256

5 17. A novel genetic mutation which results in deafness, is identified in wild dogs and is determined to be 25% penetrant with unvarying expressivity. This means that: a. All dogs which carry the mutation will be completely deaf b. All dogs which carry the mutation will have a 25% reduction in hearing ability c. 25% of dogs which carry the mutation will be completely deaf d. 75% of dogs which carry the mutation will be slightly hard of hearing e. 75% of dogs which carry the mutation will be completely deaf 18. Coat color is determined by two loci in large cats. Two pink panthers fall in love and produce a large litter of baby panthers with the following phenotypic ratios: 12/16 pink; 3/16 black; and 1/16 white. What might be the genotype of the pink progeny? a. A_ B_ b. A_ bb c. aa B_ d. aa bb e. A_ B_ and A_ bb 19. Two genes (W and X), with two alleles each, are known to contribute toward the color of wolves. A dihybrid heterozygous cross between two wolves produces pups of three different colors black, brown and grey in a ratio of 9:3:4. What is the genotype of the grey wolves? a. W_ xx b. ww X_ c. W_ X_ d. a or b are correct e. a, b or c are correct 20. A botanist is growing a newly discovered flower, called a Dragon flower, which comes in only two color varieties green and blue. The botanist has determined (1) that there are two genes which interact to produce the color varieties and (2) at least one dominant allele must be present at both loci for the green color to be seen. From these data, a dihybrid heterozygous cross will produce green and blue flowers in the ratio: a. 1:1 b. 12:4 c. 13:3 d. 9:7 e. 3:1 21. In wolves, the allele for black fur (B) is dominant to the allele for grey fur (b). In a cross between two heterozygous wolves we would expect the F1 ratio of black to grey pups to be: a. 1:1 b. 1:2 c. 2:1 d. 3:1 e. 1:4

6 22. In actuality, the F1 ratio between black and grey wolves from a heterozygous cross is observed to be 2:1. This could be explained by: a. Lethality of the homozygous dominant genotype b. Lethality of the heterozygous genotype c. A loss of the recessive allele d. Either a or b e. Either a or c 23. One gene is involved in specifying flower petal color. A true breeding red flower producing plant and a true breeding white flower producing plant are crossed to produce F1 offspring all of which have pink flowers. When the F1 offspring are selfed, when can we predict about the phenotype of the F2 generation? a. They will all be pink b. The will all be white c. They will be either red or white d. All three petal colors will be visible in the offspring e. The petals colors of the F2 will be a slightly lighter shade of pink than the F1 24. In the accompanying figure, the chance that individual IV-7 is a heterozygous carrier is. a. 1/4 b. 1/3 c. 1/2 d. 2/3 e. 3/4 25. A pure-breeding female fruit fly with a yellow body is crossed to a pure-breeding male fruit fly with a gray body. All female offspring from the cross have gray bodies and all males have yellow bodies. Body color is likely a(n) trait, and the gray allele is. a. Autosomal; dominant b. Autosomal; recessive c. X-linked; dominant d. X-linked; recessive

7 26. The amount of DNA in the cell of a newly discovered animal is measured at different points during meiosis and the mitotic cycle. It is found to have 2.4pg, 4.8pg and 9.6pg. At what phase of the meiosis is the amount of DNA likely to be 4.8pg? a. Prophase I b. Metaphase I c. Anaphase I d. Prophase II e. Telophase II 27. What dosage compensation mechanism is employed by female placental mammals? a. polar bodies b. Y-inactivation c. X-inactivation d. X nondisjunction e. X chromosome crossing over 28. A dihybrid has the genotype AaBb. After a normal mitotic division into two daughters cells, one daughter cell will have the genotype and the other will have the genotype. a. Aa; Bb b. AaBb; AaBb c. AB; ab d. Ab; ab e. AABB; aabb 29. A dihybrid has the genotype AaBb. The diagram depicts the chromosome composition of different cells from the animal. Which of the following represents the contents of a cell in G2 phase (before cell division begins)? A) Cell G B) Cell H C) Cell K D) Cell M E) Cell P

8 30) The P value is a quantitative expression of the probability that the results of another experiment of the same size and structure will deviate from expected results as much as or more than by chance. The greater the difference between observed and expected results of an experiment,. a. the lower the χ2 value and the lower the P value b. the greater the χ2 value and the greater the P value c. the greater the χ2 value and the lower the P value d. the lower the χ2 value and the greater the P value e. the greater the χ2 value; but the P value is unaffected