CoachA nucleobase is a nitrogen heterocycle: adenine (A) and guanine (G), purines; cytosine (C), thymine (T) and uracil (U), pyrimidines. A nucleoside is a nucleobase bonded by a nitrogen to C1 of ribose or 2-deoxyribose (an -glycoside). A nucleotide is a phosphate ester of a nucleoside. In nucleic acids the nucleotides are joined by phosphodiester bonds: one phosphate links O3 of one sugar to O5 of the next.
