1. Protein Structure

2. Primary Structure  The primary structure is the sequence of amino acids, which is different for each protein.

3. Primary Structure  The primary structure is the sequence of amino acids, which is different for each protein.  The sequence determines the properties of the protein.

4. Primary Structure  The primary structure is the sequence of amino acids, which is different for each protein.  The sequence determines the properties of the protein.  The info for the sequence of amino acids in a polypeptide chain is stored in a gene.

5. Primary Structure  The primary structure is the sequence of amino acids, which is different for each protein.  The sequence determines the properties of the protein.  The info for the sequence of amino acids in a polypeptide chain is stored in a gene.  A gene can be defined as ‘that length of DNA that codes for a polypeptide’

6. Primary Structure  When a mutation occurs in a gene, the mutation usually results in an altered protein – resulting in either a non- functional protein or do nothing at all.

7. Primary Structure  When a mutation occurs in a gene, the mutation usually results in an altered protein – resulting in either a non- functional protein or do nothing at all.  Human proteins are made of 20 amino acids.

8. Primary Structure  When a mutation occurs in a gene, the mutation usually results in an altered protein – resulting in either a non- functional protein or do nothing at all.  Human proteins are made of 20 amino acids.  The number of possible different sequences of the 20 amino acids is vast.

10. Secondary structure  The primary structure is bent/twisted to form a helix or pleated sheet.

11. Secondary structure  The primary structure is bent/twisted to form a helix or pleated sheet.  Pleated sheet – sections of polypeptide chains run side by side.

12. Secondary structure  The primary structure is bent/twisted to form a helix or pleated sheet.  Pleated sheet – sections of polypeptide chains run side by side.  The shapes are held in place by hydrogen bonding between certain amino acids.

13. Tertiary Structure  Globular proteins are further bent to form a complex shape.

14. Tertiary Structure  Globular proteins are further bent to form a complex shape.  This shape is both maintained by both hydrogen and disulfur bonding between certain amino acids.

15. Tertiary Structure  Globular proteins are further bent to form a complex shape.  This shape is both maintained by both hydrogen and disulfur bonding between certain amino acids.

17. Quartenary Structure  Some globular proteins are made of two or more polypeptide chains held loosely together.

18. Quartenary Structure  Some globular proteins are made of two or more polypeptide chains held loosely together.  Eg – haemoglobin has four polypeptide chains

19. Chemical Activity  Although globular proteins are large, their chemical activity resides in a small part of the molecule – the active site in enzymes.

20. Chemical Activity  Although globular proteins are large, their chemical activity resides in a small part of the molecule – the active sit in enzymes.  The bonds maintaining the shape are weak, so temperature can denature the enzyme (lose it’s chemical/biological function)

21. Chemical Activity  Although globular proteins are large, their chemical activity resides in a small part of the molecule – the active sit in enzymes.  The bonds maintaining the shape are weak, so temperature can denature the enzyme (lose it’s chemical/biological function)  Enzymes are catalysts for chemical reactions of life – they temporarily combine with substances (the substrate), forming an enzyme-substrate complex.

22. Chemical Activity  This bonding occurs at the active site – slightly changing the shape to fit the substrate.

23. Chemical Activity  This bonding occurs at the active site – slightly changing the shape to fit the substrate.  This is possible because of the weak bonds.

24. Chemical Activity  This bonding occurs at the active site – slightly changing the shape to fit the substrate.  This is possible because of the weak bonds.  If an enzyme loses it’s shape because of denaturing, or through a mutation in the amino acid sequences, the active site can be lost so the enzyme can no longer catalyse the reaction.

25. Chemical Activity