DNA Replication

DNA can replicate to make identical copies of the DNA strands. DNA replication starts with the double helix during the initiation stage when Helicase (an enzyme) is used to "unzip" the DNA. In other words Helicase seperates the two double stranded DNA to seperate strands of DNA, one being the lagging strand and the other the leading strand.

The next step in DNA replication is Elongation , this starts at the replication fork. RNA primase starts this process by adding RNA primers to the DNA strands. the primers are like a green light for the replication to start. DNA replication cannot start though, until RNA primase has added a primer. DNA polymerase starts to add DNA nucleotides from the 3' to 5' ends of the DNA. Since the nucleotides can only be added from the 3' to 5' end, the lagging strand is discontinual. polyermase will add a fragment of DNA nucleotides known as Okazaki fragments (shown in picture above). Polymerase will make a bunch of these Okazaki fragments on the lagging strand. The leading strand on the other hand is a continous replication. The leading strand is already in the 3' to 5', so DNA polymerase can start from the primers and continue without stoping or making Okazaki fragments.

The last step of DNA replication is Termination. Termination occurs when DNA polymerase reaches the end of the strands. the RNA primers are removed and ligase comes and connects the Okazaki fragments together on the lagging strand. This completes the replication of DNA.