Biochemistry
Amino Acid
Definition
Amino acids are organic molecules that serve as the building blocks of peptides and proteins. Each amino acid contains an amino group (-NH2), a carboxyl group (-COOH), and a unique side chain (R group) that determines its chemical properties. There are 20 standard amino acids encoded by DNA. Peptides are formed when amino acids link together through peptide bonds in a specific sequence. The sequence and number of amino acids determine the peptide's structure, function, and biological activity.