Regular Homework #6 Bio 111 - Gen Mager BSU (Mastering Biology)

1. a. What would be the expected frequency of agouti brown offspring in the litter?

3/16

11. e. The direction of synthesis of an RNA transcript is _____.

5' —> 3'

14. a. What is a nondisjunction?

An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell

3. b. Which of the following statements accurately describes melanin's function?

Lighter skin has less of the dark-brown eumelanin that protects cells from UV damage.

12. d. Polypeptides are assembled from _____.

amino acids

13. b. What enzyme catalyzes the attachment of an amino acid to tRNA?

aminoacyl-tRNA synthetase

3. e. Based on the risk factors discussed in the video, which of the following groups would be most likely to develop the bone disease rickets?

children born to parents with dark skin living far from the equator

6. a. Which of the following terms associated with transcription describe regions of nucleic acid?

promoter gene terminator

3. d. Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. At the same time there is selection for lighter skin to absorb more UV radiation, which is needed for vitamin D production.What evidence supports the vitamin D hypothesis for the evolution of lighter skin tones?

indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin D

13. d. What is the name of the process shown in the diagram?

initiation (of translation)

12. e. RNA processing converts the RNA transcript into _____.

mRNA

1. b. Suppose you mate two mice with the genotypes AYaBb x AYaBb . Considering only the live-born offspring, what would be the expected frequency of mice with yellow fur? Express your answer as a fraction using the slash symbol and no spaces (for example, 1/16).

2/3

1. d. In the same mouse species, a fourth unlinked gene (gene P/p) also affects fur color.For mice that are either homozygous dominant (PP) or heterozygous (Pp), the organism's fur color is dictated by the other three genes (A/a, B/b, and C/c).For mice that are homozygous recessive (pp), large patches of the organism's fur are white. This condition is called piebaldism. In a cross between two mice that are heterozygous for agouti, black, color, and piebaldism, what is the probability that offspring will have solid black fur along with large patches of white fur? (Hint: Consider each gene separately; then use the multiplication rule. For more help getting started, see Hint 1.) Express your answer as a fraction using the slash symbol and no spaces (for example, 3/16).

9/256

14. g. If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with n− 1 chromosomes, what type of error occurred?

A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell.

14. f. If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?

A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.

14. d. What kind of cell results when a diploid and a haploid gamete fuse during fertilization?

A triploid cell

14. c. Which syndrome is characterized by the XO chromosome abnormality?

Turner syndrome

13. a. Which of these is a tRNA?

B

13. c. The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____.

CUG

11. c. In the diagram below, the two blue strands represent _____.

DNA

11. d. Which of these correctly illustrates the pairing of DNA and RNA nucleotides?

GTTACG CAAUGC

3. a. Which of the following statements apply to the variation in human skin color? Select all that apply.

Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world. Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin. Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa.

14. b. When can nondisjunction occur? Choose the best answer.

In meiosis, when homologous chromosomes fail to separate In meiosis, when sister chromatids fail to separate In mitosis, when sister chromatids fail to separate All three answers are correct. (correct answer)

7. b. During translation, nucleotide base triplets (codons) in mRNA are read in sequence in the 5' → 3' direction along the mRNA. Amino acids are specified by the string of codons. What amino acid sequence does the following mRNA nucleotide sequence specify? 5′−AUGGCAAGAAAA−3′ Express the sequence of amino acids using the three-letter abbreviations, separated by hyphens (e.g., Met-Ser-Thr-Lys-Gly).

Met-Ala-Arg-Lys

7. c. What amino acid sequence does the following DNA nucleotide sequence specify? 3′−TACAGAACGGTA−5′ Express the sequence of amino acids using the three-letter abbreviations, separated by hyphens (e.g., Met-Ser-His-Lys-Gly).

Met-Ser-Cys-His

13. e. The initiator tRNA attaches at the ribosome's _____ site.

P

11. a. In the diagram below, the gray unit represents _____.

RNA polymerase

12. c. What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing

2. c. You continue your analysis by crossing the forked and twist lines. Your results are as follows: Which of the following statements best explains the outcome of this cross?

The forked mutation and the twist mutation are codominant alleles of the same locus.

14. e. Of the following chromosomal abnormalities, which type is most likely to be viable in humans?

Trisomy

10. c. Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene?

a frameshift deletion at the beginning of the gene

9. b. Based on the genetic code chart above, which of the following would be the result of this single base-pair substitution?

a nonsense mutation resulting in early termination of translation

3. c. Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?

the melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation, and folate is important in human reproduction

11. b. In the diagram below, the green unit represents _____.

the promoter

12. a. What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?

transcription

12. b. What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

translation

3. f. In what way does natural selection depend on the specific environment in which an organism lives?

when the environment changes, traits that were beneficial to an organism may become harmful and vice versa.