1. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Cellular Respiration Copyright © McGraw-Hill Companies Permission required for reproduction or display

2. Organisms Use Chemical Energy to Drive Metabolism Autotrophs - Convert radiant energy into chemical energy. Heterotrophs - Live on energy autotrophs produce.  Digestion - Breaking down large molecules with enzymes.  Catabolism - Harvesting energy from C-H. Cellular Respiration: process by which cells acquire energy

3. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Types of Processes That Use Chemical Energy to Drive Metabolism Aerobic Respiration - Oxygen gas accepts the hydrogen atom and water forms. Anaerobic Respiration - Occurs when an inorganic molecule other than oxygen accepts the hydrogen. Fermentation - Occurs when an organic molecule accepts the hydrogen atom. Formula for Cellular Respiration C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6 H 2 0 + energy

4. ATP ATP serves as cell’s energy currency ($).  ATP (Adenosine Triphosphate)  Composed of a ribose sugar, adenine base, and three phosphate groups.  Energy is stored in phosphate bonds  ATP -> ADP -> AMP  used by cells to move/drive metabolic endergonic reactions (synthesis)  Produced in mitochondria through process of cell respiration Energy Storage Molecules in Cell Respiration

5. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Aerobic Respiration Overview Copyright © McGraw-Hill Companies Permission required for reproduction or display

6. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Overview of Glucose Catabolism Cells catabolize organic molecules and make ATP two ways:  Substrate-Level Phosphorylation - Glycolysis  Aerobic Respiration - Pyruvate Oxidation - Krebs Cycle - Electron Transport Chain

7. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Overview of Glucose Catabolism Glycolysis  Biochemical pathway that produces ATP by substrate-level phosphorylation. - Yields a net of two ATP molecules for each molecule of glucose catabolized.  1 glucose molecule = 2 ATP ($$)

8. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Glycolysis Priming  Glucose Priming  Cleavage and Rearrangement Substrate-Level Phosphorylation  Reduction of NAD+  ATP Generation

9. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies

10. Glycolysis All Cells Use Glycolysis  Every living creature is capable of carrying out glycolysis. - Most present-day organisms can extract considerably more energy from glucose through aerobic respiration.

11. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Glycolysis Two molecules of NAD + (nicotinamide adenine dinucleotide) are reduced to NADH. Thus NAD + must be regenerated for glycolysis to continue  Aerobic Respiration  Fermentation

12. Fig. 9.8a

13. Fig. 9.8b

14. Oxidation of Pyruvate In stage two of glucose catabolism, pryuvate is decarboxylated, yielding:  acetylCoA  NADH  CO 2. Occurs within mitochondrian.

15. Krebs Cycle The Krebs Cycle generates two ATP molecules per glucose molecule  It harvests many energized electrons which can be directed to the electron transport chain to drive synthesis of more ATP.

16. Krebs Cycle Overview  Step A: Priming – acetyl CoA  Step B: Energy Extraction Reactions  Reaction 1 - Condensation  Reactions 2 and 3- Isomerization  Reaction 4 - First Oxidation  Reaction 5- Second Oxidation  Reaction 6 - Substrate-Level Phosphorylation  Reaction 7 - Third Oxidation  Reactions 8 and 9-Oxaloacetate Regeneration

17. Fig. 9.13a

18. Fig. 9.13b

19. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Electron Extraction Catabolism of glucose involves a series of oxidation-reduction reactions that release energy by re-depositing electrons closer to oxygen atoms. Energy is thus harvested from glucose in gradual steps, using NAD + as an electron carrier.

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21. Electron Transport Chain The electrons harvested from glucose are pumped out of the mitochondrial matrix by the electron transport chain.  Return of protons onto the matrix generates ATP.

23. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Summarizing Aerobic Respiration Oxidative reduction produces approximately 30 molecules of ATP from each molecule of glucose in eukaryotic cells.  About one-third of the energy in the chemical bonds of glucose.

24. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies

25. Regulating Aerobic Respiration Relative levels of ADP and ATP regulate the catabolism of glucose at key committing reactions.

26. Energy Storage Proteins, fats, and other organic molecules are also metabolized for energy.  Amino acids of proteins are first deaminated while fats undergo  - oxidation.

27. Overview of Glucose Catabolism Anaerobic Respiration  In the absence of oxygen, some organisms can still respire anaerobically, using inorganic molecules to accept electrons. - Examples:  Methanogens and Sulfur Bacteria

28. Fermentation Fermentation occurs in the absence of oxygen.  Electrons that result from the glycolytic breakdown of glucose are donated to an organic molecule regenerating NAD + from NADH.

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