Nucleotide

nucleotide a nucleoside that has been phosphorylated; that is, it is made up of a base, a sugar group, and one or more phosphate groups. Phosphorylation typically takes place at the 5’-position, which is why these nucleotides are also called 5’-nucleotides. Nucleotides can polymerize to form a long chain, a polynucleotide; for example, DNA and RNA. IMP, GMP, AMP, and ATP are known as ribonucleotides (5’-ribonucleotides), as their sugar group is ribose.