A codon is a sequence of three nucleotides in DNA or RNA that corresponds to a specific amino acid or a stop signal during protein synthesis. These sequences are essential for translating genetic information into proteins, which perform various functions in living organisms. Each codon is part of the genetic code, which is nearly universal across all forms of life. In the process of translation, the ribosome reads the codons on the messenger RNA (mRNA) and matches them with the appropriate transfer RNA (tRNA) molecules that carry amino acids. This interaction helps build a polypeptide chain, ultimately forming a functional protein. Codons play a crucial role in determining the structure and function of proteins.