1. Enzymes

3. Amino Acid Basic Structure

5. Primary Structure

6. Secondary Structure

7. Tertiary Structure

8. Quaternary Structure

10. Yeast

11. Sucrase

12. Human/Bacterial/Bacterial Mg

13. Catalase- H 2 O 2 -> O 2 + H 2 0

14. Catalase Lab Intro: What is catalase / function/structure Structure of proteins Overview of Lab- pH, Temperature, substrate Organism used in Lab Problem- write as a class Hypothesis- write as a class Procedure- See Vernier Biology Manual- 6B » Enzyme Action: Testing Catalase Activity

15. HOW ENZYMES FUNCTION Enzymes speed up the cell’s chemical reactions by lowering energy barriers

16. –For a chemical reaction to begin Reactants must absorb some energy, called the energy of activation Figure 5.5A E A barrier Reactants Products 12 Enzyme

17. –A protein catalyst called an enzyme Can decrease the energy of activation needed to begin a reaction Figure 5.5B Reactants E A without enzyme E A with enzyme Net change in energy Products Energy Progress of the reaction

18. A specific enzyme catalyzes each cellular reaction –Enzymes have unique three-dimensional shapes That determine which chemical reactions occur in a cell

19. Figure 5.6 Enzyme (sucrase) Glucose Fructose Active site Substrate (sucrose) H2OH2O 1 Enzyme available with empty active site 2 Substrate binds to enzyme with induced fit 4 Products are released 3 Substrate is converted to products –The catalytic cycle of an enzyme

20. 5.7 The cellular environment affects enzyme activity –Temperature, salt concentration, and pH influence enzyme activity –Some enzymes require nonprotein cofactors Such as metal ions or organic molecules called coenzymes

21. Enzyme inhibitors block enzyme action –Inhibitors interfere with an enzyme’s activity

22. –A competitive inhibitor Takes the place of a substrate in the active site –A noncompetitive inhibitor Alters an enzyme’s function by changing its shape Figure 5.8 Substrate Enzyme Active site Normal binding of substrate Enzyme inhibition Noncompetitive inhibitor Competitive inhibitor