what enzyme zips together nucleotides in dna replication
The leading strand is built by using the lagging strand of the old molecule as the template. Replication of the leading strand begins with the enzyme âprimaseâ. Primase adds a small complementary piece of RNA (~10 nucleotides), called an âRNA primerâ, near the end of the lagging strand. The RNA primer gives an enzyme called âDNA polymerase IIIâ something to attach a DNA nucleotide to. A jury-rigged design, RNA primers are necessary because DNA polymerase III can only attach nucleotides to the 3â end of a pre-existing nucleotide.