1. Chapter 6 Cellular Respiration

2. Outline Day 1 –Energy Flow and Carbon Cycling –Overview of Energy Metabolism –Redox Reactions –Electrons and Role of Oxygen –Citric Acid Cycle –Oxidative Phosphorylation Day 2 –Aerobic vs Anaerobic Metabolism –Fermentation –Energy Budget –Feedback Inhibition of Glycolysis

3. Figure 6.2 Sunlight energy enters ecosystem Photosynthesis Cellular respiration C 6 H 12 O 6 CO 2 drives cellular work Heat energy exits ecosystem ATP O2O2 H2OH2O Note: Carbon Cycles Energy Flows

4. Overview of Energy Metabolism SUN Light Energy (Photons) Photosynthesis H 2 O O 2 CO 2 Glucose Cellular Respiration CO 2 O 2 H 2 O ADP ATP Cellular Work Heat

5. Redox Reaction Redox reaction – chemical reaction where one molecule loses electrons and one gains electrons The molecule that loses electrons is said to be “oxidized”. The molecule that gains electrons is said to be “reduced.” Redox reactions are often associated with a release of energy

6. Overall Reaction of Cellular Respiration (a Redox Reaction) C 6 H 12 O 6 CO 2 O2O2 H2OH2O GlucoseOxygenCarbon dioxide Water 6 6 6 Reduction Oxidation Oxygen gains electrons (and hydrogens) Glucose loses electrons (and hydrogens)

7. High Energy Electron Carriers e−e− e−e− e−e− e−e− NADH NAD  Electrons from Glucose NAD  e−e− e−e− NADH e−e− e−e− Electrons to Oxygen High Energy Electron Carriers Recycled NAD + NADH FAD FADH 2 NADP + NADPH

8. Redox Reaction in Cellular Respiration Stepwise release of energy used to make Hydrogen, electrons, and oxygen combine to produce water Electron transport chain NADH NAD  HH HH ATP H2OH2O O2O2 2 2 2 2 2 1 e−e− e−e− e−e− e−e− e−e− e−e−

9. Three Parts of Cellular Respiration Cytoplasm Mitochondrion High-energy electrons via carrier molecules Citric Acid Cycle Oxidative Phosphorylation Glycolysis Glucose 2 Pyruvic acid ATP

10. Overview of Glycolysis Glycolysis 10 enzyme metabolic pathway (cytosol) Glucose (6 carbon molecule) 2 Pyruvate (3 carbon molecules) 2 ADP2 ATP 2 NAD + 2 NADH

11. Glycolysis – 11 Enzymes Energy investment phase Glucose 2 ATP 2 ADP INPUT Energy harvest phase OUTPUT NADH NAD  2 ATP 2 ADP 2 Pyruvic acid P P P P P P P P 12 2 3 3 –– ––

12. Three Parts of Cellular Respiration Cytoplasm Mitochondrion High-energy electrons via carrier molecules Citric Acid Cycle Glycolysis Glucose 2 Pyruvic acid ATP Oxidative Phosphorylation

13. Grooming Pyruvate for Citric Acid Cycle (Pyruvate Oxidation) (from glycolysis) (to citric acid cycle) Oxidation of the fuel generates NADH Pyruvic acid loses a carbon as CO 2 Acetic acid attaches to coenzyme A Pyruvic acid Acetic acid Acetyl CoA Coenzyme A CoA CO 2 NAD  NADH INPUT OUTPUT 2 3 1 ––

14. Citric Acid Cycle 3 NAD  ADP  P 3 NADH FADH 2 FAD Acetic acid Citric acid Acceptor molecule Citric Acid Cycle ATP 2 CO 2 INPUT OUTPUT 3 1 2 4 5 –– –– 6

15. Three Parts of Cellular Respiration Cytoplasm Mitochondrion High-energy electrons via carrier molecules Citric Acid Cycle Glycolysis Glucose 2 Pyruvic acid ATP Oxidative Phosphorylation

16. 1 2 Oxidative Phosphorylation Space between membranes Inner mitochondrial membrane Electron carrier Protein complex Electron flow Matrix Electron transport chain ATP synthase NADH NAD  FADH 2 FAD ATP ADP H2OH2O O2O2 2 P –– –– HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH 1 2 4 6 5 3 HH

17. 1 2 Figure 6.11b Space between membranes Inner mitochondrial membrane Electron carrier Protein complex Electron flow Matrix Electron transport chain NADH NAD  FADH 2 FAD O2O2 HH 2 HH HH HH HH HH HH HH HH HH HH HH HH HH HH HH H – – – – 1 2 34

18. 1 2 Figure 6.11c ATP synthase ATP ADP H2OH2O O2O2 2 P HH 546 HH HH HH HH HH HH HH HH 

19. Figure 6.12 Cytoplasm Mitochondrion NADH Citric Acid Cycle Glycolysis Glucose 2 Pyruvic acid 2 ATP 2 ATP NADH FADH 2 Maximum per glucose: 2 Acetyl CoA About 28 ATP by direct synthesis by direct synthesis by ATP synthase 22 2 6 About 32 ATP – – – – – – – – Oxidative Phosphorylation

20. Aerobic vs. Anaerobic Metabolism Citric Acid Cycle Oxidative Phosphorylation

21. Anaerobic Metabolism Glycolysis Glucose2 Pyruvate 2 ADP 2 ATP 2 NAD + 2 NADH How does NAD get recycled when there is oxygen? How does NAD get recycled when there is no oxygen?

22. Alcoholic Fermentation Glycolysis Glucose 2 Pyruvate 2 ADP 2 ATP 2 NAD + 2 NADH Alcoholic Fermentation CO 2 + Ethanol

23. Lactate Fermentation Glycolysis Glucose 2 Pyruvate 2 ADP 2 ATP 2 NAD + 2 NADH Lactate Fermentation Lactic Acid

24. Feedback Regulation of Glycolysis Glucose Glycolysis Phosphofructokinase Pyruvate Kreb Cycle CO 2 Oxidative Phosphorylation e-e- e-e- ATP ATP (Final useful product of Respiration) Inhibits Phosphofructokinase (Early enzyme of Glycolysis)

25. Figure 6.13 Food Polysaccharides Fats Proteins SugarsGlycerolFatty acids Amino acids Glycolysis Acetyl CoA Citric Acid Cycle Oxidative Phosphorylation ATP