Replication Of DNA

Prior to cell division, DNA is replicated by a DNA polymerase. DNA is unwound and hydrogen bonds between bases are broken to form two template strands

DNA polymerase needs a primer to start replication. A primer is a short strand of nucleotide which binds to the 3’ end of the DNA template strand. This allows DNA polymerase to start adding nucleotides

DNA polymerase can only add DNA nucleotides, using complementary base pairing, in one direction - to the 3’ end of the new strand that is forming. This results in the leading strand being replicated continuously and the lagging strand replicated in fragments Fragments of DNA are joined together by the enzyme ligase