1. Enzymes

2. Question: enzymes What are enzymes?

3. Enzymes Answer: 1.Proteins:enzymesproteins. 1.Proteins:most enzymes are proteins. 2.Catalyst:chemical agentaccelerates 2.Catalyst:chemical agent that accelerates a reaction without being permanently changed in the process.

4. Enzymes 3.Selective: catalyze (speed up) 3.Selective:enzymes are specific for which they will catalyze (speed up) 4.Recycled: 4.Recycled: enzymes are reusable. 5.“ase”examples:sucrase 5.“ase” endings:examples:sucrasemaltaselactase

5. Question: enzymes How do enzymes work?

6. Enzymes Answer: Enzymes lowering the free energy of activation Enzymes speed up the cell’s chemical reactions by lowering the free energy of activation.

7. Enzymes Free Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

8. Substrate substanceenzyme The substance (reactant) an enzyme acts on. Enzyme Substrate

9. Active Site restricted region enzyme bindssubstrate A restricted region of an enzyme molecule which binds to the substrate. Enzyme Active Site Substrate

10. Induced Fit changeconfigurationenzyme’s active site A change in the configuration of an enzyme’s active site (H and ionic bonds are involved). Inducedsubstrate. Induced by the substrate. Enzyme Active Site substrate induced fit

11. Enzymatic Reaction substrate (Peroxide)enzyme (Catalase in substrate (Peroxide) + enzyme (Catalase inpotato) enzyme-substrate complex  and+ catalase WaterOxygen Water Oxygen products +enzyme

12. What Affects Enzyme Activity? Two factors: Two factors: 1.Environmental Conditions 2. Concentration of enzyme and substrate

13. 1. Environmental Conditions Enzymatic reactions environmental conditions Enzymatic reactions are very specific. The following environmental conditions affect enzymatic reactions: 1.Temperature (extremes most dangerous): - high temps denature enzyme. - high temps may denature the enzyme. 2.pH (most like 6 - 8 pH - neutral)

14. Concentrations A. the concentration of enzyme Increasing enzyme concentration will increase the enzyme reaction rate. B. the concentration of substrate A higher concentration of substrate does not increase the reaction rate.

15. Mini Activity #1 Time (seconds)Number of broken Toothpicks 10 30 60 120

16. Mini Activity #1 One person’s fingers are the enzyme TOOTHPICKASE (one person is the timer, and one is the recorder) The toothpicks are the SUBSTRATE Toothpickase is a DIGESTIVE ENZYME. It breaks down toothpicks into two units. To break the toothpick, place a toothpick between the thumb and the first finger of each hand. Break the toothpick in two pieces. ALWAYS place broken toothpicks back in the container, and no peeking when breaking toothpicks!

17. Mini Activity #1 1. What was the enzyme? 2. What was the substrate? 3. What did you notice happening to the substrate as time passed? 4. Did the enzyme ever change? Why?

18. Mini Activity #2 What were to happen if we increased the concentration of rubber bands while the number of toothpicks stayed the same?

19. Mini Activity #2 Time (seconds)Number of Toothpicks Broken 20 40 60 80

20. Mini Activity #2 1. Why does toothpickase only bind to toothpicks and not rubber bands? 2. What happens when the concentration of rubber bands is higher than the concentration of toothpicks? 3. What would occur to the reaction rate if there were a higher concentration of toothpickase enzymes?