protein structure

• primary structure - number, type and sequence of amino acids in the polypeptide chain
• secondary structure - folding patterns of the chain which are stabilised by hydrogen bonds. alpha helix or beta pleated sheet
• tertiary structure - the 3D shape of a protein that is determined by the bonds formed between the amino acids
• bonds in tertiary structure - ionic bonds, hydrogen bonds, disulphide bridges
• disulphide bridges occur between cysteine amino acids between sulphur atoms
• quaternary structure - the assembly of the multiple polypeptide chains held together by bonds, and the presence of a prosthetic group