What occurs during the action of Topoisomerase?

Topoisomerase plays a crucial role in DNA replication and other processes involving DNA by relieving the torsional strain that accumulates ahead of the replication fork. During DNA replication, as the double helix is unwound by helicase, the DNA strands become positively supercoiled, creating tension. Topoisomerase acts by making temporary cuts in the DNA strands, allowing them to unwind or relax before resealing them. This action is essential for preventing knots and tangles that could obstruct the replication process.

Understanding this function helps clarify why relieving tension in DNA strands is vital during processes such as DNA replication and transcription, where maintaining the integrity of the DNA structure is necessary for the proper function of cellular processes.