6.3 Section Objectives – page 157

1. Section Objectives: • List the function of proteins. • Describe the structure of amino acids and proteins. • Explain how enzymes affect activation energy. • Describe how an enzymes shape relates to its function. 6.3 Section Objectives – page 157

2. Proteins • Aproteinis a polymer composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. • The protein polymer is called a polypeptide. • The protein monomer is called an amino acid. 6.3 Section Summary 6.3 – pages 157-163

3. The Function of Proteins • Structural proteins (e.g., hair & muscle). • Disease fighting. • Cell-to-cell signaling. • Transport. • Control chemical reactions. 6.3 Section Summary 6.3 – pages 157-163

4. Amino Acids • Each amino acid consists of a central carbon atom bonded to: • Hydrogen • Carboxyl group • Amino group • Side group (R Group) 6.3 Section Summary 6.3 – pages 157-163

5. Building a Protein • Dehydration reaction between the amino end of one amino acid to the carboxyl group of another. 6.3 Section Summary 6.3 – pages 157-163

6. Protein Shape • Protein shape determines protein function. • Shape determined by side group and surrounding environment. • Primary (1°), Secondary (2°) • Hydrophilic or hydrophobic. • Denaturation occurs when protein looses shape therefor function (e.g., temp. & pH). 6.3 Section Summary 6.3 – pages 157-163

7. Enzymes • An enzyme is a protein that changes the rate of a chemical reaction. • Enzymes lower the activation energy of chemical reactions by acting as a catalyst. 6.3 Section Summary 6.3 – pages 157-163

8. How Enzymes Work • A specific reactant (substrate) fits into the active site of the enzyme. • Active site positions reactant molecules to facilitate chemical reaction. • Enzymes themselves are unaffected by the reaction. 6.3 Section Summary 6.3 – pages 157-163

9. Transparency 5B-1

10. Transparency 5B-2

11. Transparency 5B-3

12. Transparency 5B-4

13. Transparency 5B-5

14. 1. How is the enzyme’s active site important to the reaction? The active site holds the substrate while the reaction takes place. Transparency 5B-6

15. 2. Does this enzyme get used up after one reaction? Explain. No, the enzyme is recyclable. After the products are released, the active site becomes available again. Transparency 5B-7

16. Reconnect to Objectives: • What are the functions of proteins? • What is the protein monomer? • What is the protein polymer? • What is an enzyme and how does it affect chemical reactions? • How is an enzymes shape related to its function? 6.3 Section Objectives – page 157

17. End of Chapter 5!!