Deoxyribonucleic acid (DNA) is a macromolecule that consists of deoxyribonucleotide monomers linked to each other by phosphodiester bonds. The sequence of these nucleotides contains translates into a genetic blueprint by which a cell can synthesize proteins.
This page takes a very simplified look at how DNA replicates (copies) itself. It gives only a brief over-view of the process, with no attempt to describe the mechanism.