1. Enzymes

2. Bellringer In what foods do you find the following organic molecules: - carbohydrates - proteins - lipids

3. How does food get changed to a form that can be used for energy?

4. Many substances have lactose (milk sugar) in it. Why can we not accept lactose the way it is? It’s too big! Our body cannot absorb it. We have enzymes that aid in breaking it down.

5. What are Enzymes? Enzymes are proteins. Act as catalysts to speed up a chemical reaction between reactants (substrates) that form new products. 2H 2 + O 2  2H 2 O reactants products (substrates)

6. How do Enzymes Work? All chemical reactions need energy to begin. This is called ACTIVATION ENERGY. ▫Activation energy = the energy needed to start a reaction.

7. Enzymes (catalysts) weaken the bonds that hold molecules together, lowering the amount of activation energy needed to begin the reaction. ▫This results in the reaction happening more quickly.

8. Enzymes attach to molecules called SUBSTRATES. These substrates are the reactants in the chemical reaction. The site on the enzyme where the substrate bind is called the active site.

9. The substrate(s) enters the active site which becomes the enzyme-substrate complex.

10. After undergoing a reaction in the enzyme- substrate complex, the substrate has changed and is now a product.

11. What factors affect enzyme function?

12. 1.Enzymes work best at optimum temperatures and pH. ▫extreme temperature and pH can change the shape of the enzyme, affecting the binding “active” site. ▫Conditions too far away from the ideal may cause the enzyme to denature and not work. ▫Enzymes in our body work best at 37  C (98.6  F) and at pH between 6.5 and 7.5. Acid = 0-6.9 Neutral = 7 Base = 7.1 - 14

13. 2. Are specific for what they will catalyze (only work for one type of reaction) A. B. C. Which substrate fits with the enzyme? enzyme

14. 3. Are reusable (finish a reaction exactly like they began it).

15. Enzymes are classified as which of the following biological organic compounds? A.Carbohydrates B.Lipids C.Nucleic acids D.Proteins

16. Bellringer 3/5 How does an enzyme affect the activation energy of a chemical reaction? How does that affect the rate of the chemical reaction? What two factors affect the activity of an enzyme?