Explain how DNA replicates inside a cell

DNA is made up of 4 bases (Adenine, Thymine, Guanine, Cytosine)

Adenine, guanine = purine 'Pure AGony'

Thymine and cytosine  = pyramidines

Adenine pairs with thymine (2 Hydrogen bonds - '2 people know where it is AT')

Cytosine pairs with guanine (3 hydrogen bonds)

DNA polymerase is an ezyme involved in the process. It 'unzips' the sugar phosphate backbone. The replication is semi-conservative (ie. the new molecule consists of one old stand of DNA and one new strand.