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