Final answer:
After helicase and initiator proteins attach to the origin of replication in DNA, the process of DNA replication can commence with the unwinding of the double helix and the formation of replication forks. This enables the synthesis of new DNA strands.
Step-by-step explanation:
After the attachment of the initiator and helicase proteins to the origin of replication, DNA replication can occur. The process begins with the enzymatic unwinding of the DNA double helix at specific sequences known as origins of replication. These sequences are recognized by initiator proteins that bind to the DNA, followed by the enzyme helicase, which separates the DNA strands utilizing ATP hydrolysis. As the helicase unwinds the DNA, it creates replication forks on both sides of the origin. These forks extend bidirectionally as replication progresses.
Enzymes such as topoisomerase relieve supercoiling ahead of the forks, allowing unwinding to continue smoothly. Single-strand binding proteins stabilize the separated DNA strands to prevent them from reannealing. Primase synthesizes a short RNA primer, which is necessary for DNA polymerase to initiate the addition of new nucleotides. On the leading strand, DNA is synthesized continuously, whereas on the lagging strand, synthesis is discontinuous, producing short segments known as Okazaki fragments. These fragments are later joined by DNA ligase to form a continuous strand.