1. Lesson 5

2.  Explain the term secondary structure  Explain the term tertiary structure

3.  Draw the structure of a protein and label it in as much detail as you can

4.  The coiling and pleating of parts of the polypeptide molecule

5.  Alpha Helix or Beta Pleated Sheet  Hydrogen bonds hold the structure in place  Hydrogen bonds form between oxygen and hydrogen atoms  Although hydrogen bonds are quite weak, as many bonds are formed they add stability to the structure of the protein

6.  Right hand coil, where hydrogen bonds form between oxygen and hydrogen atoms bought into close proximity  Stabilises the protein Alpha helix HYDROGEN BOND

7.  Amino acid chain folds up on itself forming anti- parallel chains  O and H atoms bought in close proximity to each other form hydrogen bonds  Stabilises the protein Beta pleated sheet

8.  Make plasticene models of alpha helix and beta pleated sheet  Describe the structures to the person next to you

9.  The overall 3D structure of the protein molecule

10.  The final 3D shape of the protein is formed when the polypeptide chain with the coils and pleats fold themselves  The 3D shape is held in place by  Hydrophobic and hydrophilic interactions  Disulphide bonds  Ionic interactions

11. Primary Secondary Tertiary Quaternary

12.  In groups of 4 each person gets a quarter of an OHT to explain one of the following:  Tertiary structure  Hydrophobic and hydrophilic interactions  Disulfide bonds  Ionic interactions  You will then present to the class

13.  Many hydrophobic R groups tend to cluster towards the interior of the protein molecule forming Hydrophobic Interactions  Hydrophilic R Groups tend to be found on the outside of proteins

14.  R groups of two amino acids contain sulphur atoms (e.g. cysteine)  If these atoms are in close proximity they form DISULPHIDE BONDS

15.  Many of the carboxylic acid and amino groups form charged groups in solution. Oppositely charged groups form IONIC BONDS

16.  The proteins shape is vital to each function  Three examples are  Enzyme  Hormone Receptor  Collagen  Why is shape important in these three cases?

17.  Enzyme: fit of the active site to its specific substrate  Hormone receptor: hormone won’t bind unless specific shape  Collagen: shaped for strength

18.  Globular  Ball structure  Hydrophobic amino acids turn inwards and hydrophilic interactions turn outwards making them water soluble  E.g. enzymes  Fibrous  Form fibres  Regular repetitive amino acid sequences  Usually insoluble  E.g. collagen

19.  Explain the term secondary structure  Explain the term tertiary structure

20.  Draw the structure of a protein and label it in as much detail as you can

21.  Complete the next part of the summary table