noun, plural: polynucleotides
A biopolymer comprised of a long, linear series of nucleotides joined together by ester linkages between the phosphoryl group of nucleotide and the hydroxyl group of the sugar component of the next nucleotide
A polynucleotide is a biopolymer comprised of monomeric units of nucleotides joined together in a chain. A nucleotide is an organic molecule that serves as the building block of nucleic acids, DNA and RNA. For instance, DNA is a biomolecule comprised of two chains of polynucleotides that complement each other at the nucleobase and form a spiral helix. Each nucleotide is made up of a nitrogenous base, a sugar component, and phosphate group(s). The nitrogenous base component may be a pyrimidine (i.e. cytosine, thymine, or uracil) or a purine (i.e. cytosine or guanine). The sugar component is a five-carbon sugar, which may be a ribose (i.e. in RNA molecules) or a deoxyribose (i.e. in DNA molecules). As for the phosphate group, a nucleotide would have a phosphoric acid component.1 In many references though, a nucleotide may have more than one phosphate attached and may be referred to as monophosphate, diphosphate, or triphosphate depending on the number of its phosphate component. In a polypeptide, the nucleotides are joined together by ester linkages between the phosphoryl group of nucleotide and the hydroxyl group of the sugar component of the next nucleotide.
Word origin: Greek poly- (many) + nucleotide
1"Nucleotides". IUPAC Gold Book. International Union of Pure and Applied Chemists. Retrieved from