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Unformatted text preview: Spring 2011 Biology 352 Exam #1 (Form A) Key L. McClenaghan Correct answers are in BOLD below. 1. The idea that organisms consist of "somatoplasm" that develops, grows and dies and a "germplasm" that is immortal and is passed to the next generation was proposed by ______. a. Darwin b. Mendel c. Weismann d. Aristotle e. Morgan 2. The DNA double helix___________ a. was discovered by Charles Darwin b. has four bases: A, U, C and G c. has a backbone composed of sugars and phosphates d. is composed of smaller amino acid subunits e. is the only nucleic acid present in most cells 3. If a strain or variety of plant or animal is said to be "true-breeding" for a particular trait, it can be inferred that the individuals in the strain are ______ for the trait. a. pleiotropic b. heterozygous c. dominant d. recessive e. homozygous 4. ________________ results in new species being produced as a result of hybridization between 2 species and a subsequent multiplication of the diploid number. a. Trisomy b. Autopolyploidy c. Aneuploidy d. Allopolyploidy e. Robertsonian translocation 5. a. b. c. d. e. Which of the following cannot be said about a chromosomal inversion? Inversions destroy old linkage relationships and create new ones. Inversions decrease the frequency of crossing over in heterozygotes. In meiosis, inversion heterozygotes display "loops" during synapsis. Pericentric inversions involve chromosome fragments containing the centromere. All of the above are true with respect to chromosomal inversions. 1 of 7 6. A man learns that both his parents had Huntington’s disease, which is caused by a dominant autosomal allele. What is the likelihood that he will have the disease if both parents were heterozygotes? a. 0% b. 25% c. 50% d. 75% e. 100% 7. In a monohybrid F1 cross (Rr x Rr), ¾ of the F2 offspring show the dominant phenotype. Of those showing the dominant phenotype a. all are RR b. all are rr c. half are Rr and half are RR d. 1/3 are Rr and 2/3 are RR e. 1/3 are RR and 2/3 are Rr 8. A couple has a child with a recessive autosomal genetic disease that neither parent displays. What is the chance that their second child will display this disease? a. 100% b. 50% c. 25% d. 6.25% e. 0% 9. A woman with a rare dominant genetic disease marries a man who lacks the disease. What is the likelihood that their first three children will have the disease? a. 1/2 b. 1/3 c. 1/8 d. 1/9 e. 1/16 10. A male mouse with the genotype AA Bb cc DD Ee is mated to a female mouse with a genotype AA bb Cc dd Ee. What is the probability that any given offspring is a male mouse with the following genotype: AA bb Cc Dd EE ? a. 1/2 b. 1/4 c. 1/8 d. 1/16 e. 1/32 11. In mammals sex determination depends on the presence of an X or Y chromosome in the sperm. In birds, sex determination depends on the presence of a. an X or Y chromosome in the sperm b. an X or Y chromosome in the egg c. a Z or W chromosome in the sperm d. a Z or W chromosome in the egg e. whether the embryo is haploid or diploid 2 of 7 12. When crossing AaBb x AaBb individuals, the expected genotypic ratio of the offspring would be: a. 9 AaBb: 3 Aabb; 3 aaBb; 1 aabb b. 1 AABB: 2 AaBB: 1 aaBB: 2 AABb: 4 AaBb: 2 aaBb: 1 AAbb: 2 Aabb: 1 aabb c. 1 AABB: 2 AaBB: 2 aaBB: 2 AABb: 2 AaBb: 2 aaBb: 2 AAbb: 2 Aabb: 1 aabb d. 9 AABB: 3 Aabb: 3 aaBb: 1 aabb e. 3 aabb: 1 AABB 13. Consider an F1 generation of trihybrids (e.g. Aa Bb Cc) that is testcrossed. Assuming that these 3 genes are all on different chromosomes, how many phenotypic classes would be observed in the testcross progeny? a. 1 b. 2 c. 4 d. 8 e. 16 14. Assuming that the 3 genes in Question 17 above are on the same chromosome and that crossing over occurs, how many phenotypic classes would be observed in the testcross progeny? a. 1 b. 2 c. 4 d. 8 e. 16 15. In human Y chromosomes, regions called the ___________ regions allow tetrad formation by the X and Y chromosomes during meiosis. a. telomeric b. SRY c. TDF d. paracentric e. pseudoautosomal 16. A couple has a child with a recessive X-linked genetic disease that neither parent displays. What is the chance that their second child will display this disease? a. 25% for the girls; 25% for the boys b. 50% for the girls; 50% for the boys c. 0% for the girls; 100% for the boys d. 0% for the girls; 50% for the boys e. 100% for all the children 17. An individual with Klinefelter’s Syndrome probably obtained an extra X chromosome as a result of___________________________. a. a somatic mutation b. non-disjunction involving the X chromosome c. non-disjunction involving an autosome d. Barr body formation e. The presence of an O chromosome 3 of 7 18. X-linked traits were first discovered in Drosophila by _______________. a. Punnett b. Mendel c. Morgan d. Sturdevant e. Aristotle Questions 19 – 21 relate to the following paragraph: Coat color in dogs depends on the action of at least two genes. At one locus an epistatic inhibitor of coat color pigment (I_) prevents the expression of color alleles at another independently assorting locus, thereby producing white coat color. When the following genotype exists at the inhibitor locus (ii), the alleles of the second locus will be expressed with genotype iiB_ producing the black phenotype and iibb producing the brown phenotype. 19. The dominant gene for coat color is _____________. a. black b. brown c. white d. it’s a codominant system e. insufficient information 20. When dihybrid white dogs are mated, what would be the phenotypic ratio in the offspring? a. 12:3:1 b. 9:7 c. 9:3:3:1 d. 3:1 e. 1:2:1 21. The above is an example of ________________________. a. recessive epistasis b. duplicate recessive epistasis c. duplicate interaction d. dominant epistasis e. none of these 22. For a genetic maternal effect a. the genotype of the offspring determines the phenotype of the offspring b. the phenotype of the mother determines the phenotype of the offspring c. the genotype of the mother determines the phenotype of the offspring d. the genotype of the father determines the phenotype of the offspring e. the environment experienced by the mother determines the phenotype of the offspring 4 of 7 Questions 23 – 25 refer to the following pedigree (NOTE: Assume mutation is not occurring!) 23. Which of the following marriages would be considered consanquineous? a. I-1 X I-2 b. II-5 X II-6 c. III-2 X III-3 d. II-1 X II-2 e. There are no consanguineous marriages in this pedigree. 24. According to the pedigree, individuals IV-2 and IV-3 are __________. a. identical twins b. fraternal twins c. Siamese twins d. Minnesota twins e. adopted 25. Which of the following is the most likely mode of inheritance of this trait? a. X-linked recessive b. X-linked dominant c. Autosomal dominant d. Autosomal recessive e. All of these are consistent with the pedigree 5 of 7 26 . For the pedigree at the right, the mutation may be a. dominant autosomal b. recessive autosomal c. X-linked recessive d. A, B or C e. A or B only For Questions 27 and 28 consider the following scenario: In corn, the alleles C and c at one gene result in colored versus colorless seeds, Wx and wx at another gene produce nonwaxy versus waxy endosperm, and the third gene has alleles Sh and sh that produce plump versus shrunken endosperms. When plants grown from seeds heterozygous for each pair of genes (e.g. trihybrids) are testcrossed to plants having colorless, waxy, shrunken seeds, the follow progeny are obtained: Phenotype colorless, nonwaxy, shrunken colorless, nonwaxy, plump colorless, waxy, shrunken colorless, waxy, plump colored, waxy, shrunken colored, waxy, plump colored, nonwaxy, shrunken colored, nonwaxy, plump Total Number Observed 84 974 20 2349 951 99 2216 15 6708 27. Which of the following genotypes would be found in nonrecombinant gametes? a. c wx Sh b. C Wx Sh c. c Wx Sh d. c wx sh e. C wx sh 28. By looking at the double recombinants in the F2, which of the following statements is true with respect to the linear sequence of these genes on the chromosome? a. The gene for endosperm waxiness (Wx, wx) is located between the other two. b. The gene for seed color (C, c) is located between the other two. c. The gene for endosperm shape (Sh, sh) is located between the other two. d. These 3 genes are on 3 different chromosomes. e. Can't say without additional information. 29. A genetic cross is made between an individual with the CcDd genotype and one with the ccdd genotype. The offspring are 40 CcDd; 38 ccdd; 12 Ccdd; 10 ccDd. What is the recombination frequency between the two loci? a. 10% b. 12% c. 22% d. 40% e. 78% 6 of 7 30. In a genetic recombination experiment, you find that a and b are 15 cM apart, b and c are 12.4 cM apart, a and c are 2.6 cM apart. The relative order of the genes is: a. abc b. cab c. acb d. the genes are unlinked e. cannot be determined Use the following table to answer Questions 31- 33. 31. Which of the following would encode Met? a. A Leu codon with a transversion in its first residue b. A Val codon with a transversion in its first residue c. A Leu codon with a transition in its first residue d. A Val codon with a transition in its first residue e. Both A and D are correct 32. The genetic code is said to be degenerate or redundant. Which two codons illustrate this? a. AAA and AGA b. GTT and GAT c. TTT and TCT d. GAT and GAC e. ACA and GCA 33. Which amino acid has a codon that could become a nonsense mutation with a single base substitution? a. His b. Trp c. Met d. Asp e. Phe` 7 of 7 ...
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This note was uploaded on 05/07/2011 for the course BIOLOGY 352 taught by Professor Townsend during the Spring '08 term at San Diego State.
- Spring '08