DNA, computer artwork. DNA (deoxyribonucleic acid) is the molecule that controls the growth, development and functioning of all living things. It comprises a pair of sugar-phosphate strands spiralling around each other in a double helix. The strands are linked by the interactions between bases on each strand. There are four types of base: adenine (A), thymine (T), cytosine (C) and guanine (G). A only links to T, and C only links to G, making each strand complementary to its partner. DNA encodes information as a sequence of base pairs. The strands contain sections called genes, which are recipes for proteins, the main structural and functional components of the body..