Amino acids

A polymer of amino acids is called a polypeptide.

All amino acids share common structures (see List of amino acids). Amino acids consist of an amino group and a carboxyl group connected by an alpha carbon. The R group, also known as side chain, differs with each amino acid. The side chain’s physical and chemical properties determine the functional role of the amino acid in the polypeptide. Because of the unique characteristic of the side group, an amino acid can be hydrophobic, hydrophilic, acidic or basic. Amino acids are connected with peptide bonds.

Figure 1: Structure of a representative amino acid. All amino acids contain an amino group and a carboxyl group joined to a central carbon atom. The side group varies between amino acids and it is this which gives rise to their unique chemical and physical properties.