Chapter 16 Mutation, Repair and Recombination

Lysine and arginine are two amino acids with similar sized “R” (side-) groups and similar biochemical behavior (for example, both are basic residues). A mutation results in substitution of lysine for arginine and has no detectable effect on the function of that protein. Which statement best applies to this situation?

•The mutation is a silent mutation.

•The mutation is a frameshift mutation.

•The amino acid change is conservative.

•The amino acid change is silent.

•This organism displays no codon bias.

Question

Which of the following represents a correct or acceptable phrase in genetics?

•Mutant protein

•Protein mutation

•DNA mutation

•A and C

•All of the above

Question

Which of the following statements is correct about the bases in DNA under normal circumstances:

•Adenine should pair with thymine.

•The bonds holding guanine and cytosine together are stronger than the bonds holding adenine and thymine together.

•A purine always binds to a pyrimidine.

•A substitution of adenine for guanine is a transition mutation.

•All of the above

Question

Carcinogens and the Ames Test

Repair mechanisms

Photo reactivation repair Base excision repair Nucleotide excision repair Transcription coupled repair Mismatch repair

Undamaged DNA

UV light (mutagenic agent)

EMS, NG (mutagenic agent)

Pyrimidine dimers Methylated base

Original Base

Photolyase

Visible lightAlkyl Transferase

Inactivated after action

Replication dependent repair

Which of the following repair pathways do not involve the use of a homology-dependent repair system?

a. Base excision repairb. Photo reactivation repairc. Transcription coupled repaird. Nucleotide excision repaire. Mismatch repair

Question

•Which of the following DNA duplexes is most stable?

5’ AATTAATTAATTAATTAATT 3’ 3’ TTAATTAATTAATTAATTAA 5’

5’ GGCCGGCCGGCCGGCCGGCC 3’3’ CCGGCCGGCCGGCCGGCCGG 5’

• Both are equally stable.• B is more stable than A.

Question

Which of the following repair pathways do not involve the use of a homology-dependent repair system?

a. Base excision repairb. Photo reactivation repairc. Transcription coupled repaird. Nucleotide excision repaire. Mismatch repair

Question