Final answer:
Topoisomerase II is an enzyme that relaxes the supercoiling of the DNA that is created during the unwinding process of DNA replication, by cutting and rejoining the DNA strands to prevent strand breakage and replication errors.
Step-by-step explanation:
The function of topoisomerase II in DNA replication is crucial for maintaining DNA integrity and allowing the replication process to proceed smoothly. This enzyme plays a significant role in resolving the tension that is created by the unwinding of DNA during replication. As DNA helicase unwinds the double helix at the replication fork, the DNA ahead of the fork becomes overwound or supercoiled, which can hinder the progression of replication. Topoisomerase II works by cutting the DNA's phosphate backbone, allowing the DNA to relax and relieve the supercoiling stress. This cutting and subsequent rejoining of the DNA strands prevents the DNA from becoming too tightly coiled, which can lead to strand breakage and replication errors. Hence, topoisomerase II is essential for making the DNA more accessible for replication machinery, ensuring a successful and accurate replication process.