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.

The biuret test for proteins.

Students should be able to relate the structure of proteins to properties of proteins named throughout the specification.