Describe the process of semi-conservative replication.

DNA is a double-stranded molecule with a base unit on each side held together by hydrogen bonds. A binds to T and C binds to G. DNA polymerase facilitates the localised breaking of these hydrogen bonds. Free nucleotides bind to the exposed bases and form a new strand onto each of the original strands. This process of forming a new strand is also facilitated by the action of DNA polymerase.