What role does topoisomerase play in DNA replication?

What role does topoisomerase play in DNA replication?

• A. Joins Okazaki fragments
• B. Unwinds the DNA strands
• C. Corrects supercoiling ahead of the replication fork
• D. Synthesizes RNA primers

Answer: (C)

Topoisomerase plays a crucial role in managing the topological challenges that arise during DNA replication, particularly concerning supercoiling. When the double helix of DNA is unwound to allow for replication, the tension created results in supercoiling ahead of the replication fork. Topoisomerase alleviates this strain by introducing temporary breaks in the DNA strands. It either cuts one or both strands, allowing them to unwind and then rejoining them, thereby preventing tangles and knots. This action is essential for the progression of the replication fork and ensures that replication can occur smoothly and efficiently. The other roles mentioned in the options are filled by different enzymes. For instance, the joining of Okazaki fragments is performed by DNA ligase, RNA primers are synthesized by primase, and unwinding of the DNA strands is primarily the function of helicase. Therefore, the specific function of correcting supercoiling is what distinguishes the role of topoisomerase in the context of DNA replication.

Topoisomerase plays a crucial role in managing the topological challenges that arise during DNA replication, particularly concerning supercoiling. When the double helix of DNA is unwound to allow for replication, the tension created results in supercoiling ahead of the replication fork. Topoisomerase alleviates this strain by introducing temporary breaks in the DNA strands. It either cuts one or both strands, allowing them to unwind and then rejoining them, thereby preventing tangles and knots. This action is essential for the progression of the replication fork and ensures that replication can occur smoothly and efficiently.

The other roles mentioned in the options are filled by different enzymes. For instance, the joining of Okazaki fragments is performed by DNA ligase, RNA primers are synthesized by primase, and unwinding of the DNA strands is primarily the function of helicase. Therefore, the specific function of correcting supercoiling is what distinguishes the role of topoisomerase in the context of DNA replication.