DNA
DNA (deoxyribonucleic acid) is the genetic information found in most organisms. It is arranged into structures called chromosomes. The structure of DNA was identified as being a 'double-helix' by Watson and Crick in 1953.
DNA is composed of 4 bases; Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). These form complementary bases pairs of AT and GC.