The DNA molecule is a double helix therefore, either side can serve as a template to be copied by RNA. DNA stores the genetic code in the nucleus of every cell. This genetic information is stored in a sequence of nitrogenous bases that get transcribed or copied by mRNA(messenger RNA). Every three bases is called a codon. The mRNA codon is actually the information that gets translated once the mRNA leaves the nucleus and attaches to a ribosome in the cytoplasm. There, each codon will be translated into a particular amino acid, by the transfer RNA. As each amino acid gets assembled into a chain, it forms a polypeptide. When the polypeptide reaches a "stop" codon, the whole molecule detaches from the ribosome and proceeds to fold into a three dimensional shape. It is now a protein.