DNA Replication

This week in AP Biology we talked about DNA replication. DNA replication is the process by which a DNA molecule is copied, and how cells repair their DNA. DNA replication is a very important process in all living things. The replication of a DNA molecule begins in particular sites called origin of replication. Initiation proteins bind to the the origin of replication and separate the two strands which form a replication bubble. Then the DNA moves in both directions of the DNA strand until it is copied. DNA polymerase adds nucelotides to the growing chain working in a 5` to 3` direction. The replication occurs continuously along the 5` to 3` strand, this is called the leading strand and the strand that runs 3` to 5` is copied in segments and it is called the lagging strand. The lagging strand is synthesized in Okazaki fragments which are sealed together by DNA ligase which then forms a continuous DNA strand.