Final answer:
Helicase unwinds the double helix to allow strand separation, while DNA polymerase synthesizes new complementary strands, following an RNA primer in a 5' to 3' direction. Mutations in helicase can prevent strand separation, disrupting replication. DNA ligase completes the process by sealing the nicks in the DNA backbone.
Step-by-step explanation:
In the process of DNA replication, helicase plays a vital role by unwinding the double helix at the origin of replication. It works by breaking the hydrogen bonds between the base pairs, which allows the two strands of DNA to separate. This separation of strands is essential to provide single-stranded templates for the new DNA to be synthesized. Topoisomerase aids this process by relieving the tension in the DNA ahead of the replication fork, while single-stranded binding proteins prevent the DNA strands from reannealing. DNA polymerase then synthesizes the new complementary strands by adding nucleotides in a 5’ to 3’ direction. There are leading and lagging strands due to the antiparallel nature of DNA, leading to continuous synthesis on the leading strand and discontinuous synthesis on the lagging strand, forming Okazaki fragments.
If helicase is mutated, the DNA strands will not separate correctly, impeding the entire replication process. DNA polymerase requires a primer, synthesized by primase, to begin adding nucleotides. Following the insertion of nucleotides, RNA primers are removed and replaced with DNA, and DNA ligase seals the nicks in the sugar-phosphate backbone, completing the formation of a continuous strand.