1. Proteins Proteins make up more than 50% of the dry weight of cells
Proteins are instrumental almost all aspects of an organisms life

2. Structural Proteins Function Example Support
Collagen & elastin in animal connective tissues
Keratin in hair, horns & feathers

3. Storage Proteins Function Example Storage of amino acids
Ovalbumin in egg whites stores amino acids for developing embryo
Casein in mammal milk is a major source of amino acids for baby mammals

4. Transport Proteins Function Example Transport of other substances
Hemoglobin transports oxygen from the lungs to other parts of the body
Proteins transport molecules across cell membranes

5. Hormonal Proteins Function Example
Coordination of an organism’s activities
Insulin regulates the concentration of sugar in the blood of vertebrates

6. Receptor Proteins Function Example
Response of cell to chemical stimuli
Receptors built into the membrane of a nerve cell detect chemical signals from other nerve cells

7. Contractile & Motor Proteins
Function
Example
Movement
Actin & myosin are responsible for the movement of muscles
Cilia & flagella

8. Defensive Proteins Function Example Protection against disease
Antibodies combat bacteria & viruses

9. Enzymatic Proteins Function Example Catalyze chemical reactions
Digestive enzymes catalyze the hydrolysis of polymers in food

10. Protein Structure
Monomers of amino acids bond together to form polymers called polypeptide chains
Amino acidspolypeptideprotein

13. Primary Structure: A sequence of amino acids

14. Secondary Structure: Twisting or bending of the polypeptide chain

15. Tertiary Structure: Three dimensional, folded structure

16. Fig. 5-21e
Tertiary Structure
Quaternary Structure

17. A ribbon model of lysozyme A space-filling model of lysozyme
Fig. 5-19
Groove
Groove
(a)
A ribbon model of lysozyme
(b)
A space-filling model of lysozyme

18. Hydrophobic interactions and van der Waals interactions Polypeptide
Fig. 5-21f
Hydrophobic
interactions and
van der Waals
interactions
Polypeptide
backbone
Hydrogen
bond
Disulfide bridge
Ionic bond

19. Quaternary Structure: When two or more polypeptides fold together

20. Denature To cause a protein to lose its shape
Caused by acid, base, temperature etc

21. Enzyme A molecule that catalyzes (speeds up) a chemical reaction
Most enzymes are proteins

22. Substrate The reactant being catalyzed
Example: The enzyme, amylase requires the substrate, starch.