DNA molecule in a petri dish, computer artwork. DNA (deoxyribonucleic acid) forms a shape called a double helix, which is like a twisted ladder. The uprights of the ladder are sugarphosphate backbones, and the rungs are paired nucleotide bases. The bases come in 4 varieties, adenine, guanine, thymine and cytosine. The order of the base pairs is a code which carries the bodys genetic information in sections called genes.
