The general process of DNA replication.

. The name DNA
double helix is composed of two single strands in opposite directions, and when replication begins, the double chain opens to form a copy fork (from the open starting point to one direction) or a copy bubble (replicative bubble, formed from the open starting point in both directions). Two single chains do templates separately. Each synthesizes a new DNA strand. Since the direction of one strand of DNA is in the direction of 5'→3', the direction of the other chain is in the direction of 3'→5', but the DNA polymerase in the organism can only catalyz DNA synthesis from the direction of 5' →3'. So how can two chains with different directions be templates? The problem was solved by the Japanese scholar Mr. Okazaki.it turns out that when the female chain is templated in the direction of 3'→5', the lead chain is copied and synthesized into a 5'→3' direction, and the leading chain is in the same direction as the direction of the copy fork opening, so the synthesis of the leading chain is Continuously, while the other parent chain DNA is in the direction of 5' →3', it serves as a template, copying and synthesized many short chains in the direction of 5' →3', called the entourage strand, which is in the opposite direction to the opening direction of the copy fork. The entourage chain can only be synthesized in the form of fragments called Okazaki fragments, which contain 1000-2000
nucleotides
, or 100-00 nucleotides in the ebony. Finally, several Gangsaki fragments are connected into a complete chain. Since the synthesis of the leading chain is continuous, and the synthesis of the entourage chain is not continuous, THE DNA replication in general is semi-continuous (Figure 16-4).Figure 16-4 Semi-continuous replication of DNAThe entire process of DNA replication can be artificially divided into three stages, the first of which is the initial phase of DNA replication, which includes the starting point, the direction of replication, and the formation of the trigger, and the second stage is the extension of the DNA chain, including the formation of the lead chain and the entourage chain and the filling of gaps and connections to the Gangazaki fragments after the formation and removal of RNA quotations. The third stage is the termination phase of DNA replication. More than 30 enzymes and
protein
molecules are involved throughout DNA replication, and we will highlight their roles at various stages of DNA replication.
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