Objectives E – Recall the different structures of proteins and the test for proteins. C – Describe how a peptide bond is formed. Describe the different structure of proteins A – Explain how the structures of a polypeptide build up and how changes to this may affect function

Proteins Polymer Monomer is amino acid 20 amino acids

Amino group Carboxylic group

Amino acids 20 different amino acids Joined together by condensation Peptide bond is formed

Polypeptide is many amino acids joined together

condensation

Polypeptide – primary structure Chain of amino acids Held together by peptide bonds Differences due to the type, number and position of amino acid

Secondary structure Folding of polypeptide chain forming an alpha helix or a beta sheet

Secondary structure Held together by hydrogen bonds

Tertiary structure Further folding of secondary structure, held together by hydrogen, ionic, disulphide and hydrophobic bonds

Quaternary structure More than one polypeptide joined together

The alpha helix are shown The beta pleated sheets are shown The disulphide bridges are shown by purple atoms bonded together. The bits of the protein chain which are just random coils and loops are shown as bits of "string".

Monosaccharide 1-4 glycosidic link Maltose Fructose Sucrose Galactose Hexose Condensation Hydrolysis Peptide bond Tertiary structure Secondary structure Lactose Primary structure Quartenary structure Hydrogen bonds Alpha helix Beta pleated sheet