A chemical compound consisting of a heterocyclic base, a sugar, and one or more phosphate groups, these compounds form the structural units of DNA.
An ester of a nucleoside and phosphoric acid. Nucleotides are nucleosides that have a phosphate group attached to one or more of the hydroxyl groups of the sugar (ribose or deoxyribose). In short, a nucleotide is a hybrid molecule consisting of a purine or pyrimidine base covalently linked to a five-membered sugar ring which is covalently linked to a phosphate group. While (polymerized) nucleotides are the structural units of a nucleic acid, free nucleotides that are not an integral part of nucleic acids are also found in tissues and play important roles in the cell, e.g., ATP and cyclic AMP.
A combination of purine and pyrimidine bases, 5-carbon atom sugar, and phosphoric acid.