11.09.2008

DNA replication

DNA replication is the double-stranded DNA in the cell division process before replication, copy results of a double-stranded into the same two double-stranded (if it is to copy the normal course of the case), each with double-stranded, like the original double-stranded . This process is known as the semi-replication mechanism to enable the successful completion of the. Copy can be divided into the following phases:
Start-up phase: helicase in the local launch of the double helix structure of DNA single-strand molecule, primer-identification initiation site in order to remove a section of DNA as a template, in accordance with the 5 'to 3' direction of short-chain RNA synthesis. The formation of RNA primer.
DNA fragment generation: to provide a primer 3'-OH on the basis of the end, DNA polymerase chain two catalytic DNA replication at the same time, as the process can only be copied by the 5'-> 3 'direction of synthesis, so a chain Can be synthesized in a row, another sub-chain synthesis, in which every chain has become a short Okazaki fragments (Okazaki fragments).
Hydrolysis of RNA primer: When DNA synthesis after a certain length, DNA polymerase hydrolysis of RNA primer, Butian gap.
DNA ligase will fragment of DNA phosphodiester bond linking it to complete the formation of the DNA molecule.
Finally, the new synthetic DNA fragments of the enzyme in the rotation with the help of re-forming spiral.