1. Cellular respiration: Harvesting chemical energy

2. Respiration overview ProcessCellular location InputsOutputs Glycolysis Citric acid cycle (and formation of acetyl CoA) ETC and oxidative phosphorylation

3. Respiration overview ProcessCellular location InputsOutputs GlycolysisCytosolGlucose2 pyruvate 2 NADH 2 ATP Citric acid cycle (and formation of acetyl CoA) ETC and oxidative phosphorylation

4. Respiration overview ProcessCellular location InputsOutputs GlycolysisCytosolGlucose2 pyruvate 2 NADH 2 ATP Citric acid cycle (and formation of acetyl CoA) Mitochondrial matrix Pyruvate6 CO 2 2 ATP 8 NADH 2 FADH 2 ETC and oxidative phosphorylation

5. Respiration overview ProcessCellular location InputsOutputs GlycolysisCytosolGlucose2 pyruvate 2 NADH 2 ATP Citric acid cycle (and formation of acetyl CoA) Mitochondrial matrix Pyruvate6 CO 2 2 ATP 8 NADH 2 FADH 2 Oxidative phosphorylation Mitochondrial inner membrane High energy electrons O 2 34 ATP Water

6. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP Rearrangement of molecules: Splitting sugar Going from one 6-C molecule to two 3-C molecules

7. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP The glucose is primed for cleavage (it is phosphorylated twice) It is split forming two 3-C molecules with phosphate groups The 3-C molecules are converted to pyruvate

8. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP What’s going on with the energy? Two stages: Energy investment Energy payoff

9. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP What’s going on with the energy? Two stages: Energy investment Energy payoff The phosphorylation of the 6-C molecule requires 2 ATP

10. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP What’s going on with the energy? Two stages: Energy investment Energy payoff 4 ATP are produced through substrate-level phosporylation

11. Glycolysis InputsOutputs Glucose2 pyruvate 2 NADH 2 ATP What’s going on with the energy? Two stages: Energy investment Energy payoff Net gain of 2 ATP and 2 NADH

12. What happens next? Glucose Aerobic respiration Fermentation In the presence of oxygen In the absence of oxygen Is split in Glycolysis Yielding Pyruvate Anaerobic respiration

13. Citric acid cycle In the presence of oxygen, pyruvate enters the mitochondrial matrix A derivative of pyruvate that enters the CAC Pyruvate is transformed to Acetyl Co A in the three reactions –Pyruvate’s carboxyl group is released (CO 2 is emitted) –Remaining 2-C molecule is oxidized (NAD+ is reduced to NADH) –Co-enzyme A is added Pyruvate + NAD + + CoA Acetyl- CoA + NADH + CO 2 + H +

14. Citric acid cycle What’s going on with the molecules? Acetyl-CoA (2-C molecule) binds with oxaloacetate (4-C molecule) Citrate (6-C molecule) is rearranged and decarboxylated (CO 2 is emitted) Oxaloacetate (4-C molecule) is regenerated CAC

15. Citric acid cycle What’s going on with the energy? Energy Yield 3 NADH 1 FADH 2 1 ATP (Per acetyl CoA) CAC

16. Math check (per glucose) ProcessReduced electron carriers generated Glycolysis2 ATP Oxidation of pyruvate to Acetyl coA Citric acid cycle2 ATP Total4 ATP

17. Math check (per glucose) ProcessReduced electron carriers generated Glycolysis2 NADH Oxidation of pyruvate to Acetyl coA 2 NADH Citric acid cycle6 NADH 2 FADH 2 Total10 NADH 2 FADH 2

18. Math check (per glucose) ProcessReduced electron carriers generated Glycolysis2 NADH Oxidation of pyruvate to Acetyl coA 2 NADH Citric acid cycle6 NADH 2 FADH 2 Total10 NADH 2 FADH 2 These move to the mitochondrial membrane

19. Oxidative phosphorylation During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis

20. Oxidative phosphorylation During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis Energy stored from a hydrogen ion gradient drives cellular work

21. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q    VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the electron transport chain form a proton gradient? The ETC is a collection of molecules embedded in the mitochondria inner membrane

22. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q   VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the electron transport chain form a proton gradient? The ETC is a collection of molecules embedded in the mitochondria inner membrane Each component becomes successively reduced (when it gains electrons) and oxidized (when it passes the electrons to the next molecule

23. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q    VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the electron transport chain form a proton gradient? The ETC is a collection of molecules embedded in the mitochondria inner membrane Each component becomes successively reduced (when it gains electrons) and oxidized (when it passes the electrons to the next molecule Each one is more electronegative than the next

24. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q    VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the electron transport chain form a proton gradient? The ETC is a collection of molecules embedded in the mitochondria inner membrane Each component becomes successively reduced (when it gains electrons) and oxidized (when it passes the electrons to the next molecule Each one is more electronegative than the next Oxygen is at the end of the ETC (the final electron acceptor). It becomes reduced to water.

25. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q    VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the electron transport chain form a proton gradient? The ETC is a collection of molecules embedded in the mitochondria inner membrane Each component becomes successively reduced (when it gains electrons) and oxidized (when it passes the electrons to the next molecule) Each one is more electronegative than the next Oxygen is at the end of the ETC (the final electron acceptor). It becomes reduced to water. The ETC uses the exergonic flow of electrons to pump protons into the inter membrane space.

26. Oxidative phosphorylation Protein complex of electron carriers H+H+ H+H+ H+H+ Cyt c Q   VV FADH 2 FAD NAD + NADH (carrying electrons from food) Electron transport chain 2 H + + 1 / 2 O 2 H2OH2O ADP + P i Chemiosmosis Oxidative phosphorylation H+H+ H+H+ ATP synthase ATP 21 How does the proton gradient form ATP? The electrochemical gradient causes protons to be drawn to ATP synthase (one of the only ways to re-enter the mitochondrial matrix) Proton flow spins the rotor on the ATP synthase This spins a rod inside The movement of the rod facilitates the synthesis of ATP

27. Math check ProcessReduced electron carriers generated Glycolysis2 NADH Oxidation of pyruvate to Acetly coA 2 NADH Citric acid cycle6 NADH 2 FADH 2 Total10 NADH ~30 ATP 2 FADH 2 ~4 ATP

28. Math check ProcessReduced electron carriers generated Glycolysis2 NADH Oxidation of pyruvate to Acetly coA 2 NADH Citric acid cycle6 NADH 2 FADH 2 Total10 NADH ~30 ATP 2 FADH 2 ~4 ATP 38 ATP from one glucose!

29. What happens when oxygen is not present to accept the electrons? Glucose Aerobic respiration Fermentation In the presence of oxygen In the absence of oxygen Is split in Glycolysis Yielding Pyruvate Anaerobic respiration

30. Fermentation ProcessLocationInputsOutputs GlycolysisCytosolGlucose NAD + 2 pyruvate NADH 2 ATP GeneralCytosolPyruvate (or a derivative) NADH NAD + Reduced organic molecule The partial breakdown of sugars

31. Fermentation ProcessLocationInputsOutputs GlycolysisCytosolGlucose NAD + 2 pyruvate NADH 2 ATP AlcoholicCytosol (bacteria, plants and fungi) Pyruvate derivative NADH NAD + CO 2 Ethanol The partial breakdown of sugars

32. Fermentation ProcessLocationInputsOutputs GlycolysisCytosolGlucose NAD + 2 pyruvate NADH 2 ATP Lactic acidCytosol (animals, fungi, and bacteria) Pyruvate NADH NAD + Lactate The partial breakdown of sugars

33. Fermentation 2 ADP + 2 PiPi 2 ATP Glucose Glycolysis 2 NAD + 2 NADH 2 Pyruvate + 2 H + 2 Acetaldehyde2 Ethanol (a) Alcohol fermentation 2 ADP + 2 PiPi 2 ATP Glucose Glycolysis 2 NAD + 2 NADH + 2 H + 2 Pyruvate 2 Lactate (b) Lactic acid fermentation 2 CO 2 Allows glycolysis to continue, but only produces 2 ATP per glucose

34. You should: Understand that respiration is a catabolic process (glucose is broken down and energy released is captured in ATP) Know the inputs and outputs of glycolysis, the citric acid cycle, oxidative phosphorylation, and fermentation Understand how the above processes operate