AP BIOLOGY

Detailed explanation-1: -Topoisomerase works at the region ahead of the replication fork to prevent supercoiling.

Detailed explanation-2: -7. Which of the following enzymes remove supercoiling in replicating DNA ahead of the replication fork? Explanation: Strand separation creates topological stress in the helical DNA structure which is relieved by the action of topoisomerases.

Detailed explanation-3: -Topoisomerase I is the target enzyme for the inhibitory effects of camptothecins. It modulates the topological structure of DNA by inducing transient DNA breaks. Single-strand breaks help to remove excessive positive and negative DNA supercoils, which arise during DNA replication and transcription.

Detailed explanation-4: -DNA gyrase, is the type II topoisomerase enzyme that is primarily involved in relieving positive supercoiling tension that results due to the helicase unwinding at the replication fork.