Question

topoisomerase has what function? _______

A) elongation of DNA at a replication fork by adding nucleotides to the existing chain

B) unwinding of the double helix

C) relieving strain in the DNA ahead of the rep fork

D) stabilizing single stranded DNA at the Rep.fork

E) addition of methyl groups to bases of DNA

Explain why C is correct and why the other choices are incorrect as well as mention the names of the enzymes for the indicated function

Answer 1

The correct answer is option (C) relieving strain in the DNA ahead of the rep fork

The function of Topoisomerase is to relieve the strain in the DNA ahead of the replication fork. Because while DNA replication and transcription DNA becomes overwound ahead of a replication fork. And the enzymes which participate in the overwinding or underwinding of DNA is called Topoisomerase.

The other choices are incorrect because:

1. (A) elongation of DNA at a replication fork by adding nucleotides to the existing chain is the function of an enzyme called DNA Polymerase.
2. (B) unwinding of the double helix is the function of DNA helicase.
3. (D) stabilizing single stranded DNA at the Rep.fork is the function of Helicase.
4. (E) addition of methyl groups to bases of DNA is the process called DNA methylation.