Caption

DNA molecule. Computer artwork of a double helix, representing a molecule of deoxyribonucleic acid (DNA). The double helix is formed from two sugar- phosphate backbones (tubes). Between the two strands are nucleotide bases (not seen). There are four different bases: guanine, cytosine, thymine and adenine. Guanine always pairs with cytosine and adenine always pairs with thymine. DNA contains sections, called genes, which encode the body's genetic information. Genes determine each cell's structure, function and behaviour.