Question

1. In prokaryotes, in the DNA repair mechanism called mismatch repair,

A) enzymes that perform the repair can distinguish the new strand of DNA from the template strand because the template strand is methylated.

B) if a mismatch is detected, the 2 bonds that the mismatched nucleotide forms with adjacent nucleotides are cleaved and that single nucleotide is removed and replaced by the correct nucleotide.

C)each new nucleotide is "proofread" by DNA polymerase.

D) A and B

E) all of the above

2.DNA proofreading is an activity of

A) DNA ligase.

B)DNA polymerase.

C) RNA polymerase.

D)the MutS protein.

E) DNA glycosylase.

Answer 1

1. B) if a mismatch is detected, the 2 bonds that the mismatched nucleotide forms with adjacent nucleotides are cleaved and that single nucleotide is removed and replaced by the correct nucleotide.

In prokaryotes, in the DNA repair mechanism called mismatch repair. Mismatch repair which corrects the mismatched nucleotide after DNA replication.

2. B) DNA polymerse.

DNA proofreading is an activity of DNA Polymerase enzyme. All the DNA polymerase enzyme (Pol I, Pol II and Pol III) have the ability to proofread the incorrect base pair by 3' to 5' exonuclease activity.