DNA - Deoxyribonucleic acid
The molecule that encodes genetic information. It is made up of units called nucleotides, each including one of four bases—adenine (A), cytosine (C), guanine (G), or thymine (T). The molecule comprises two strands held together by bonds between A and T and between G and C, resulting in a structure often referred to as a double helix. It is found in the nucleus of cells, within bacteria and some viruses, as well as in organelles such as mitochondria and chloroplasts.