1. Ground Rules of Metabolism Chapter 6 Part 2

2. Types of Metabolic Pathways  A metabolic pathway is any series of enzyme- mediated reactions by which a cell builds, rearranges, or breaks down an organic substance Anabolic pathways build molecules Catabolic pathways break apart molecules Cyclic pathways regenerate a molecule from the first step

3. Controls Over Metabolism  Feedback mechanisms can adjust enzyme production, or activate or inhibit enzymes  Regulatory molecules can bind to an allosteric site to activate or inhibit enzymes Feedback inhibition

4. Allosteric Control

5. Animation: Allosteric activation

6. Animation: Allosteric inhibition

7. Feedback Inhibition

8. Animation: Feedback inhibition

9. Redox Reactions  Oxidation-reduction reactions (paired reactions) A molecule that gives up or donate electrons is oxidized A molecule that accepts or gain electrons is reduced Coenzymes can accept molecules in redox reactions (also called electron transfers)

10. ATP Synthesis  Coenzymes deliver electrons to electron transfer chains for ATP synthesis  Electron transfer chain A series of redox reactions in membrane-bound enzymes or molecules that release energy in small, controlled steps

11. Fig. 6-17, p. 101 nutrients Energy-releasing reactions breakdown products (carbohydrates, fats, proteins) ADP + P i oxidized coenzymes (e. g., carbon dioxide; water) reduced coenzymes ATP molecules of life Energy-requiring reactions small organic molecules

12. Key Players in Metabolic Reactions

13. Animation: Enzymes and activation energy

14. Animation: Enzymes and temperature

15. Video: Alcohol, enzymes, and your liver