1. Proteins and Enzymes: Life Functions Chemistry of Life Notes Part 4

2. Proteins THINK: What do we already know about proteins?

3. Proteins… Monomer: Amino Acid Chemical Formula: – Has C, H, O, N, and usually S.

4. The R groups…

5. Functions (review): – Provide structure for tissues and organs – Antibodies – Proteins express DNA – Transport/movement – Carry out cell metabolism in the form of enzymes

6. Enzymes Enzyme: Type of protein that act as catalyst Catalyst: Substance that speeds up chemical reactions without being used up What do enzymes do? – Lower the activation energy needed to get started – Make reactions work FASTER

8. Activation Energy The energy needed to make a reaction get started Without enzymes the energy needed is too much!

9. Enzymes and Substrates Enzymes fit with substances like puzzle pieces. The Substrate = the substance an enzyme matches Very specific fit!

10. ACTIVATION SITES Activation site: Where the enzyme binds to substrate Analogy: Lock-and-key fit Activation site

11. Enzyme-Substrate Complex 1.Enzyme “finds” the correct substrate and matches at activation site 2.When matched, chemical reaction begins 3.Products are formed and released – Enzyme goes again!

12. Stop and Think: What part of a chemical reaction is the substrate??

13. ACTIVATION SITES Draw and label the ENZYME-SUBSTRATE COMPLEX: Activation site

14. ENZYMES HELP PUT SUBSTRATES TOGETHER Reactants

15. ENZYMES HELP TAKE APART SUBSTRATES

16. OPTIMUM CONDITIONS

17. Denaturation Proteins are denatured when a change in the shape of a protein reduces or destroys enzyme function Conditions that lead to denaturation: – Temperature (heat) – pH – Salt concentration – Overall environment – Chemicals

18. Stop and Think #1 Why does changing the shape of the enzyme matter?

19. Stop and Think #2 How are enzymes important to chemical reactions?

20. Stop and Think #3 How is the amount of product in a chemical reaction related to the amount of reactant?

21. Stop and Think #4 What do you think would happen to the rate of a chemical reaction if the amount of substrate were decreased?

22. Stop and Think #5 What do you think would happen to the rate of a chemical reaction if the amount of enzyme were decreased?

23. Stop and Think #6 What do you think would happen to the rate of a chemical reaction if another substrate with a similar shape were to “sneak in” and bind with the enzyme for the original substrate?