Reviewed by: Mary Anne Clark, PhD
A codon is the amino acid coding unit in DNA or messenger RNA. Each codon corresponds
to a specific amino acid, and the string of codons in mRNA specifies the order of amino
acids in the encoded protein. Each codon consists of a set of three adjacent nucleotides,
also called triplets, in mRNA that base-pair with the three bases of the corresponding
anticodon of a tRNA molecule that carries a particular amino acid. The ribosome, where
protein synthesis occurs, has binding sites where the tRNAs can match up with their
corresponding codons in the mRNA.