Describe the structure of proteins (5)

The primary structure of proteins consist of the sequence of amino acids that are joined by peptide bonds. These amino acids are joined together via a condensation reaction. The secondary structure is formed when the primary structure does not remain flat. The secondary structure curls into an alpha helix or beta pleaded sheet when hydrogen bonds form between the amino acids. The tertiary structure forms when the secondary structure coils or folds further. Hydrogen and ionic bonds from in the polypeptide chain. Disulfide bonds also form too. For proteins containing one polypeptide chain, this is their final 3D structure. Finally, the quaternary structure is made from two or more polypeptide chains.