Cellular Respiration

1. Cellular Respiration Organic + Oxygen Carbon + Water + Energy Compounds Dioxide • Cellular respiration: A catabolic energy yielding pathway in which oxygen and organic fuels are consumed and ATP is produced • An aerobic process—it requires oxygen Summary equations:

2. Energy Conversion Fuel rich in chemical energy Waste products poor in chemical energy Energy conversion Heat energy Gasoline  Oxygen Carbon dioxide  Water Combustion Kinetic energy of movement Energy conversion in a car Heat energy Cellular respiration Carbon dioxide  Water Food  Oxygen ATP Energy for cellular work Energy conversion in a cell

3. Cellular Respiration •By oxidizing glucose, energy is taken out of “storage” and made available for ATP synthesis Oxidation Glucose loses electrons (and hydrogens)  6 6 H2O  6 C6H12O6 O2 CO2 Glucose Oxygen Carbon dioxide Water Reduction Oxygen gains electrons (and hydrogens)

4. *Multistep open hydroelectric system Metabolic Disequilibrium

5. Cellular Respiration *Substrate-level phosphorylation 3 metabolic stages: *glycolysis *Krebs cycle *electron transport chain and oxidative phosphorylation *Oxidative phosphorylation

6. Mitochondrion Cytoplasm Cytoplasm Cytoplasm Plant cell Animal cell Animal cell Plant cell Cytoplasm Cytoplasm Mitochondrion Mitochondrion High-energy electrons carried by NADH High-energy electrons carried mainly by NADH High-energy electrons carried by NADH High-energy electrons carried mainly by NADH Glycolysis Citric Acid Cycle Citric Acid Cycle 2 Pyruvic acid Electron Transport Glycolysis Electron Transport Glucose ~38 ATP per glucose ATP ~34 2 ATP ATP 2 ATP ATP ATP Figure 6.6

7. Cellular Respiration Glycolysis harvests chemical energy by oxidizing glucose to pyruvate.

8. Cellular Respiration 3) Addition of another phosphate group 1) Glucose is phosphorylated 4) Cleavage into 2 3-carbon sugars 2) G-6-P is rearranged 5) Conversion b/w the 2 3-carbon sugars

9. Cellular Respiration Glycolysis: Energy Payoff Phase 6) Two components: *electron transfer *Phosphate group addition 9) Loss of water 7) ATP production 10) ATP production 8) Rearrangement of phosphate group

10. Fermentation aerobic anaerobic

11. Cellular Respiration The Krebs cycle: energy-yielding oxidation The junction b/w glycolysis and the Krebs cycle: Multienzyme complex: 1) Removal of CO2 2) Electron transfer *pyruvatedehydrogenase 3) Addition of CoA

12. Cellular Respiration The Krebs cycle: energy-yielding oxidation 8) electron transfer Malatedehydrogenase 1) Addition of 2 Carbons Citrate synthase 2) Isomerization Aconitase 3) *Loss of CO2 *electron transfer Isocitrate dehydrogenase 7) Rearrangement of bonds Fumarase 4) *Loss of CO2 *electron transfer a-ketoglutaratedehydrogenase 6) electron transfer Succinate dehydrogenase 5) substrate-level phosphorylation Succinyl CoA-synthetase

13. Cellular Respiration *Multi-step open system Electron transport and ATP synthesis

14. Cellular Respiration Generation and maintenance of an H+ gradient *Exergonic flow of e-, pumps H+ across the membrane *chemiosmosis high energy electrons

15. Cellular Respiration *How does the mitochondrion couple electron transport and ATP synthesis? ATP synthase

16. Versatility of Cellular Respiration • In addition to glucose, cellular respiration can “burn”: • Diverse types of carbohydrates • Fats • Proteins Food Proteins Polysaccharides Fats Sugars Fatty acids Glycerol Amino acids Citric Acid Cycle Acetyl CoA Glycolysis Electron Transport ATP