A) This is due to the fact that thymine dimers cause DNA to buckle and interfere with DNA replication.
B) This is best explained by the fact that DNA polymerase can only add nucleotides to a 3' end.
C) This is not a problem because the telomere is a nonessential repeating unit.
D) This is true only if the organism has been exposed to excessive amounts of ultraviolet rays of sunlight.
E) This problem is resolved by telomerase, which extends the 3' end of the DNA.
The following questions refer to the following simple metabolic pathway table ( ( enzyme a enzyme b ) ( A label_arrow_right_over B label_arrow_right_over C ) (~%5 ~%6) )
16) According to Beadle and Tatum's one gene-one enzyme hypothesis, how many gene(s) is (are) necessary for this pathway?
E) It cannot be determined from the pathway.
17) One strain of a diploid organism is homozygous for a recessive allele coding for a defective enzyme a. Another strain is homozygous for a recessive allele coding for a defective enzyme b. Crossing those two strains will result in a strain that would grow on which of the following?
A) a minimal medium supplemented with both A and B
B) a minimal medium supplemented with A
C) a minimal medium supplemented with B
D) All of the above will support the growth of the new strain.
18) Which of the following represents a similarity between RNA and DNA?
A) the presence of uracil
B) the presence of a double-stranded helix
C) nucleotides consisting of a phosphate, sugar, and nitrogen base
D) the presence of an OH group on the 3' carbon of the sugar
E) repair systems that correct genetic code errors
19) A particular triplet of bases in the coding sequence of DNA is AGT. The corresponding codon for the mRNA transcribed is
E) either UCA or TCA, depending on wobble in the first base.
The following questions refer to Figure 17.1, a table of codons.
20) A possible sequence of nucleotides in DNA that would code for the polypeptide sequence phe-leu-ile-val would be
A) 5' TTG-CTA-CAG-TAG 3'.
B) 3' AAA-GAA-TAA-CAA 5'.
C) 5' AUG-CTG-CAG-TAT 3'.
D) 3' AAA-AAT-ATA-ACA 5'.
E) 3' AAC-GAC-GUC-AUA 5'.
21) What amino acid sequence will be generated, based on the following mRNA codon sequence?
C) complementary to the corresponding triplet in rRNA.
D) changeable, depending on the amino acid that attaches to the tRNA.
E) the part of tRNA that bonds to a specific amino acid.
50) Which of the following is not true of RNA processing?
A) Ribozymes may function in RNA splicing.
B) RNA splicing may be catalyzed by spliceosomes.
C) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.
D) The presence of introns may facilitate crossing over between regions of a gene that code for polypeptide domains.
E) Exons are excised and hydrolyzed before mRNA moves out of the nucleus.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
Answer the following on a separate sheet of paper (20 pts)
51) Science, Technology, and Society Our civilization generates many potentially mutagenic chemicals (pesticides, for example). Some argue that civilization modifies the environment in ways that increase exposure to other mutagens, notably UV radiation. What role should government play in identifying mutagens and regulating their release to the environment?
1) Answer C
2) Answer A
3) Answer C
4) Answer D
5) Answer A
6) Answer E
7) Answer A
8) Answer D
9) Answer E
10) Answer C
11) Answer D
12) Answer E
13) Answer C
14) Answer B
15) Answer E
16) Answer C
17) Answer B
18) Answer C
19) Answer D
20) Answer B
21) Answer E
22) Answer A
23) Answer D
24) Answer C
25) Answer A
26) Answer D
27) Answer C
28) Answer D
29) Answer A
30) Answer C
31) Answer A, B
32) Answer A
33) Answer D
34) Answer E
35) Answer D
36) Answer D
37) Answer A
38) Answer E
39) Answer B
40) Answer D
41) Answer B
42) Answer D
43) Answer E
44) Answer E
45) Answer B
46) Answer C
47) Answer A
48) Answer C
49) Answer A
50) Answer E