The chemical structure of an amino acid consists of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain or R group. The R group determines the specific properties of each amino acid and contributes to the diverse functions they serve. Amino acids are the building blocks of proteins, linked together by peptide bonds in a specific sequence to form polypeptides. This sequence ultimately dictates the protein's structure and function within biological systems.