DNA, or deoxyribonucleic acid, is a polymer made up of two strands of nucleotides. Each nucleotide is made up of a phosphate group, pentose sugar and nitrogenous base (of which there are 4 types). These nucleotides are joined up together to form one strand and the other strand is made up through complementary base pairing. These two strands are then twisted together to form a double helix structure. The sequence of bases within the DNA codes for amino acids, which will eventually be translated to form specific proteins required within the body.