Other amino acids avoid water and are called hydrophobic, such as isoleucine, phenylalanine, and valine. The amino acid cysteine has a chemically reactive side chain that can form bonds with ...

This image illustrates the general structure of an amino acid.The central carbon atom (C) is bonded to a hydrogen atom (H), an amino group (NH2), a carboxyl group (COOH), and a variable side chain (R ...