Summary Amino acids, peptides and protein structure.

Amino acids are the monomers from which proteins are made. The general structure of an amino acid as: where NH2 represents an amine group, COOH represents a carboxyl group and R represents a side chain. The twenty amino acids that are common in all organisms differ only in their side group. A condensation reaction between two amino acids forms a peptide bond. Dipeptides are formed by the condensation of two amino acids. Polypeptides are formed by the condensation of many amino acids. A functional protein may contain one or more polypeptides. The role of hydrogen bonds, ionic bonds and disulfide bridges in the structure of proteins. Proteins have a variety of functions within all living organisms. The relationship between primary, secondary, tertiary and quaternary structure, and protein function.