What role do helicases play in DNA replication?

Helicases are essential enzymes in the process of DNA replication because they are responsible for unwinding the DNA double helix. This unwinding is crucial as it separates the two strands of the DNA molecule, allowing access for the replication machinery to synthesize new strands. By breaking the hydrogen bonds between the complementary base pairs, helicases create a replication fork where the DNA strands can be copied.

This unwinding action is foundational for the entire replication process, as it enables other enzymes, such as DNA polymerases, to attach to the single strands and synthesize new DNA. Consequently, without the function of helicases, the DNA could not be successfully replicated, as the strands would remain in their double helical form and inaccessible for copying.