2. Enzyme Review Are you ready?

3. Define Catalyst. A molecule that allows stable molecules to react quickly.

4. What is an enzyme? and what is it made of?

5. An enzyme is a biological catalyst It is a protein and made of a long chain of amino acids

6. What do enzymes do? They speed up chemical reactions by……. Lowering Activation Energy needed to start the reaction.

7. What enzyme did we use in our labs? Catalase What reaction does it speed up? The breakdown of Hydrogen Peroxide into water and oxygen. H2O2--------) H2O + O2

8. Why are enzymes necessary? So that chemical reactions in living things can happen fast enough Example- In the human body— Hydrogen Peroxide would break down without catalase, but it would be so slow that H2O2 would build up and become TOXIC!

9. Name the two kinds of reactions. Exothermic Endothermic

10. Which requires energy input and which gives off heat? Endothermic RXNS require energy to be added IN to keep going. Exothermic RXNS give off energy. Energy EXITS.

11. What does it mean to say a reaction is “spontaneous”? Once it starts it will continue until the end. No energy input is required after the activation energy.

12. Define Activation Energy. The measure of how hard molecules have to collide to get a reaction to begin. The push to get a reaction started.

13. Which kind of molecules have high activation energy— Stable or Unstable? Stable molecules don’t interact easily– they have HIGH activation energy. Need a bigger push to get started. Unstable molecules react more easily-- They are highly reactive, have LOW activation energy.

14. What is KMT? Kinetic Molecular Theory The idea that molecules are always moving and when they collide hard enough with one another, they will react.

15. What happens when enzymes are exposed to heat? A little heat can speed up a reaction by making the molecules move faster---- BUT

16. What happens when there is too much heat or the wrong pH? Enzymes DENATURE They unravel. They no longer keep the same shape so they won’t fit the substrate any more. They need to be in their OPTIMUM range of temp or pH to function the best!

17. Explain Lock and Key Model Enzyme is the Lock Substrate is the Key The active site is the Keyhole

18. What happens at the active site? The enzyme and the substrate bind together. What is Induced Fit?

19. Amino acids in the active site Attract amino acids on the substrate due to different charges and polarity They interact and the bonds are broken and new ones form.

20. Can an enzyme be used in any reaction?

21. NO They are very SPECIFIC, SELECTIVE, PICKY They only work with one substrate.

22. Are enzymes used up in a reaction? NO They can be used over and over again.

23. What happens when you add more enzyme? The rate of reaction increases– Happens faster

24. What happens when you add more substrate? No change in rate, BUT You get more product.

25. Thanks for playing Enzyme Review