DNA is a polymer made from four different nucleotides. The DNA polymer is made up of repeating nucleotide units. Each nucleotide consists of a common sugar and a phosphate group, with one of four different bases attached to the sugar. The long strands of DNA have alternating sugar and phosphate sections, and one base is attached to each sugar.
DNA contains four bases, called A, C, G and T. A sequence of three bases is the code for a particular amino acid. The order of the bases controls the order in which amino acids are assembled to produce a particular protein.
