What is the function of the enzyme topoisomerase in DNA replication?
A) relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix
B) elongating new DNA at a replication fork by adding nucleotides to the existing chain
C) reattaching the hydrogen bonds between the base pairs in the double helix
D) building RNA primers using the parental DNA strand as a template

Question

Quizplus · Accepted Answer

Topoisomerase is responsible for relieving the strain caused by the unwinding of the double helix during DNA replication. It does this by cleaving one or both strands of the DNA, allowing it to unwind, and then rejoining the strands to release the tension that has built up.

B, C, and D are incorrect because elongation of new DNA, reattaching hydrogen bonds between base pairs, and building RNA primers all involve different enzymes that work at different stages of DNA replication.

What Is the Function of the Enzyme Topoisomerase in DNA