3. Objectives Differentiate between reactants and products in a chemical reaction. Describe the process of the chemical reaction and explain how enzymes catalyze chemical reactions by lowering the activation energy. Recognize that enzymes are specific and are not used up in a chemical reaction. Create analogies that demonstrate understanding of the role of enzymes.

4. Chemical Reaction Reactants Products Activation Energy ENZYME Catalyst SubstrateActive Site Induced Fit

5. ENZYME Biological Catalyst Catalyst = speeds up the rate of chemical reaction by LOWERING activation energy. Substrate or Reactants bind to active site. Makes reactions happen FASTER Active Site restricted region enzymebinds substrate A restricted region of an enzyme molecule which binds to the substrate.

6. Chemical Reactions Recipe Ingredients are to Cake as Reactants are to Product Reactants or Substrate are the starting substances. Chemical reactions allow living things to grow, develop, reproduce and adapt. New Products are made as atoms are rearranged.

7. Chemical Reactions Reactants Products C 6 H 12 O 6 + O2 CO 2 + H 2 0 Just like cake is made with flour, sugar, and other ingredients mixed together, it is not cake until you bake it. The key to starting a chemical reaction is energy. yields

8. 7 7 So How Do Enzymes Work? weakening bonds which lowers activation energy Enzymes work by weakening bonds which lowers activation energy Activation Energy = minimum amount of energy needed for reactants (substrate) to form Products (new substance)

9. Enzymes Free Energy Progress of the reaction Reactants Products Activation Energy Without Enzyme With Enzyme Lowers Activation Energy

10. 9 Enzyme-Substrate Complex substance enzyme substrate The substance (reactant) an enzyme acts on is the substrate Enzyme Substrate Binds to Active Site

11. 10 Induced Fit shape A change in the shape of an enzyme’s active site Induced Induced by the substrate

12. Examples of Enzymes at Work Notice simple to more complex drawings. Each illustrates how an enzyme works. See if you can identify Enzyme, Reactants (Substrate), Products, active site, and induced fit. Remember the job of the enzyme is to LOWER the activation energy so the chemical reaction works FASTER.

13. Reactants (Substrate ) Enzyme Chemical Reaction Products Enzyme Notice Reactants (Substrate bind to enzyme where chemical reaction occurs faster because the activation energy is lowered (less energy needed than without enzyme). The enzyme is ready to act again and does NOT become part of the Products. Active Site

14. Reactants/SubstrateProducts

15. Notice Name of Enzyme Notice Name of Substrate Name of Enzyme ends with “ASE” and is named according to its job.

16. Enzymes Have a specific job Do NOT get used up or become part of product. Lowers the activation energy needed to get the reaction started. Makes the reaction happen faster.

17. Can you finish these analogies about Enzymes and create your own? An enzyme is to a reaction, as a ____ is to a lock. Ose is to a carbohydrate as ____ is to an enzyme. Ingredients are to a cake, as _________ are to the Product. key Ase Reactants

18. Review Key Vocabulary and Relate to ENZYMES

19. Chemical Reaction Reactants Products Activation Energy ENZYME Catalyst SubstrateActive Site Induced Fit

20. Proceed to Quiz or Review PowerPoint