In a previous article, I gave a brief overview of the complex molecular mechanisms governing DNA replication. Now, I will focus specifically on the replication enzyme DNA polymerase.
DNA polymerase is the enzyme responsible for synthesizing new strands of DNA, complementary to the sequence of the template strand. The unidirectional DNA polymerase progresses along the template strand in a 3′-5′ direction, since it requires a pre-existing 3′-OH group for the adding of nucleotides. The daughter strand is, consequently, synthesized in a 5′-3′ direction (opposite to the direction of movement of the polymerase since the two strands have an anti-parallel orientation).