What is the function of topoisomerase?
A) relieving strain in the DNA ahead of the replication fork
B) elongating new DNA at a replication fork by adding nucleotides to the existing chain
C) adding methyl groups to bases of DNA
D) unwinding of the double helix
E) stabilizing single-stranded DNA at the replication fork

Question

Quizplus · Accepted Answer

Topoisomerase is responsible for relieving the strain on the DNA ahead of the replication fork. It breaks the DNA strands, rotates them, and then rejoins them to prevent supercoiling of the DNA during replication.

Answer: D 
 The unwinding of the double helix is performed by helicase. Topoisomerase is not directly involved in this process but works to relieve the stress on the double helix created by the unwinding process.

Therefore, the correct answer is A.

What Is the Function of Topoisomerase