TJ. The Enzymes A portion of the double helix is unwound by a helicase. A molecule of a DNA polymerase binds to one strand of the DNA and begins moving along it in the 3' to 5' direction, using it as a template for assembling a leading strand of nucleotides and reforming a double helix. In eukaryotes, this molecule is called DNA polymerase epsilon (ε). Because DNA synthesis can only occur 5' to 3', a molecule of a second type of DNA polymerase (delta, δ, in eukaryotes) binds to the other…