Replikasjonsgaffelen

Replikasjonsgaffelen, often referred to as the replication fork, is a Y-shaped structure that forms during DNA replication. It is the site where the DNA double helix is unwound, allowing each strand to be used as a template for the synthesis of a new complementary strand. The unwinding of the DNA is facilitated by enzymes called helicases, which break the hydrogen bonds holding the two strands together.

As the helicase moves along the DNA, it separates the two strands, creating two single strands that are now accessible for DNA polymerase. DNA polymerase is the enzyme responsible for synthesizing the new DNA strands. It reads the template strand and adds complementary nucleotides to build the new strand. Because DNA polymerase can only synthesize DNA in one direction (5' to 3'), the process of replication at the fork is asymmetric.

One of the new strands, known as the leading strand, is synthesized continuously in the same direction as the replication fork is moving. The other strand, the lagging strand, is synthesized discontinuously in short fragments called Okazaki fragments. These fragments are later joined together by another enzyme called DNA ligase. The coordinated action of these enzymes at the replication fork ensures that the entire genome is accurately duplicated before cell division. The stability and progression of the replication fork are crucial for maintaining genomic integrity.