Final answer:
DNA strands separate at the origin of replication under the action of helicase, and various other enzymes like topoisomerase and single-strand binding proteins facilitate the replication process by relieving supercoiling tension and stabilizing unwound strands.
Step-by-step explanation:
The origin of replication is the specific location on a double-stranded DNA molecule where the strands separate to allow for replication. The enzyme helicase unwinds the double helix at this point, forming two replication forks that extend bidirectionally. Following this, single-strand binding proteins coat the single strands to prevent them from re-annealing or forming secondary structures.
Topoisomerase acts ahead of the replication forks to relieve the supercoiling tension by nicking the DNA, allowing the strands to rotate and relieve the tension. An RNA primer is synthesized by primase, which provides the starting point for DNA polymerase to begin adding nucleotides, thereby creating the new DNA strands. If the helicase enzyme is mutated, it could lead to an inability to separate the DNA strands, thereby impeding the replication process.