Final answer:
Helicase is responsible for unwinding the DNA double helix and initiating the formation of replication forks, where DNA replication occurs. Mutations in helicase can prevent the replication fork formation and stop DNA replication. Topoisomerases, single-stranded binding proteins, and DNA ligase work in concert at the replication fork for the synthesis and stabilization of DNA.
Step-by-step explanation:
The role of helicase and replication forks are closely linked in DNA replication. Helicase is an enzyme that uses the energy from ATP hydrolysis to separate the two DNA strands at the origin of replication. This separation by helicase leads to the formation of Y-shaped structures known as replication forks, where the DNA replication process occurs. These replication forks allow for the synthesis of new DNA strands by providing a single-stranded template for enzymes like DNA polymerases. If helicase is mutated, the DNA strands will not be unwound, and replication forks will not be formed, effectively halting DNA replication at its initial stage.
Topoisomerases play a role ahead of the replication fork by cutting and rejoining the DNA's phosphate backbone to relieve supercoiling caused by unwinding. Single-stranded binding proteins stabilize the unwound DNA, and primase synthesizes an RNA primer which is extended by DNA polymerases to form new DNA strands. DNA ligase then seals the gaps between Okazaki fragments on the lagging strand, producing a continuous new strand.