1. AP Biology Serrano High School
Enzymes
AP Biology
Serrano High School

2. General Information Globular proteins Unique 3 dimensional shape
Active site: pocket or groove where substrate binds

3. General Information Catalysts Speed up chemical reactions
Lower activation energy
Not used up in chemical reaction

4. General Information Substrate specific Enzyme substrate pairs
Catalase – hydrogen peroxide
Sucrase – sucrose

5. Action – Induced Fit Model
Substrate binds to enzyme at active site
Interaction between substrate and active site

6. Action – Induced Fit Model
Bonds in substrate stressed
Bonds break
Products released

7. Action – Induced Fit Model
Substrate binds to enzyme at active site
Interaction between substrate and active site
Bonds form between reactants

8. Temperature & Rate Increasing temperature increases rate
Increase temperature increases speed of molecules
Increase speed of molecules increases number of collisions

9. Temperature & Rate Optimal temperature
Temperature that produces max. rate.

10. Temperature & Rate Temperature above optimal
Enzyme denatured (changes shape)
Reaction drops then stops

11. pH & Rate
Optimal pH
pH with at max. rate

12. pH & Rate Above optimal – rate decreases
Lower [H+] interferes with enzyme shape

13. pH & Rate Below optimal – rate decreases
Higher [H+] interferes with enzyme shape

14. pH & Rate
Extreme changes – rate zero
Enzyme denatures

15. Control of Chemical Reactions
Inhibitors – Competitive
Inhibitor competes with substrate for active site

16. Control of Chemical Reactions
Inhibitors – Noncompetitive
Inhibitor binds to site other than active site

17. Control of Chemical Reactions
Allosteric Enzymes
Two conformations – active & inactive
Activator stabilizes active form
Inhibitor stabilizes inactive form