Energy Releasing Pathways ( Cellular Respiration )

1. Energy Releasing Pathways (Cellular Respiration) I. Introduction A. History

2. 1. Antoine Lavoisier in the 1700’s can make wine without living organisms 2. Wohler and VonLeibigsupported this idea, but Schwann showed juice would not ferment without yeast. 3. In 1860 Pasteur proved ethanol amountproportional to the amount of yeast present

3. 4. In 1897 the Buchner brothers == steps of glycolysis key to fermentation 5. In the early 1900’s Szent-Györgyi designed Citric Acid Cycle,failed to show relationship to fermentation 6. Krebs in 1938 linked glycolysis to citric Acid Cycle via enzyme CoAKreb’s Cycle

4. Cellular Respiration or releasing energy from glucose with the use of O2. Figure 7.1

5. B. Aerobic Respiration

6. Overview of Aerobic Respiration Figure 7.2

7. 1. Glycolysis a. Where

8. Glycolysis cytoplasm

9. b. Steps

10. Investment Three components: Splitting & Harvest Figure 7.3

11. Investment 1. Enzyme attaches a P from ATP to glucose after diffusing into the cell Prevents glucose from diffusing back out of cell 2. Attach another P from second ATP to glucose Generates a balanced molecule with a P at either end. Splitting 1. Enzyme cuts molecule into two G3P’s 2. Liberates H and NAD+ steals the electrons from H to form NADH + H+ 3. The hole left by the leaving H is backfilled by Pi This step balances the G3P with a P on either end This happens twice or once for each G3P How many NADH + H+are formed per glucose?

12. Harvest 1. Enzyme directly transfers a P from G3P to ADP to make ATP How many times does this happen to make how many ATP’s? 2. Makes two molecules of pyruvate Figure 7.4 Substrate-level ATP synthesis

13. c. Outcomes

14. 1. 2ATP are used by the cell. The next two outcomes only happen if oxygen is present in the cell. 2. NADH+H+ mitochondria and electron transport chain 3. 2pyruvic acids are combined to CoAto go to the mitochondria and the Kreb’s cycle

15. 2. Transport to Mitochondria a. Where

16. Cytoplasm to Mitochondrial Matrix Figure 7.5

17. b. Steps

18. Taxi anyone? Figure 7.6

19. Transport 1. Enzyme splits off a CO2 from a pyruvate which liberates electrons from H and given to NAD+ to form NADH+ H+ to make a 2C acetyl group 2. Combine acetyl group to Co-enzyme A to be transported to the mitochondria

20. c. Outcomes

21. The next two outcomes only happen if oxygen is present in the cell. 1. NADH+ H+ mitochondria and electron transport chain 2. 2pyruvate combined to2CoAgo to the mitochondria and the Kreb’s cycle

22. 3. Kreb’s Cycle a. Where

23. Six step Kreb’s cycle mitochondrial matrix Figure 4.20 Figure 7.5

24. b. Steps

25. Acetic acidadded tooxalacetic acid to make citric acid Acetic acid Oxaloacetic acid Citric acid Figure 7.6

26. Destroying 1. Enzyme combines acetic group with oxaloacetic acid to begin cycle 2. Enzyme splits out CO2 and liberates H to NAD+to make NADH+ H+ How many CO2 are liberated? 3. As H’s are removed then a Pi jumps on only to be removed to form ATP Rearranging 1. Enzyme reshapes molecule to liberate more H’s to rebuild oxaloacetic acid 2. Liberates H and NAD+ or FAD+ steals the electrons to make NADH+ H+ or FADH2 This happens twice or once for each acetic group

27. c. Outcomes

28. 3.NADH+ H+ and FADH2 to electron transport chain 1.ATPused 2.CO2diffuses into cytosol and lost

29. 4. Electron Transport Chain a. Where

30. Inner Mitochondrial Membrane protein based reactions  oxidation/reduction reactions release energy to make ATP viaATP synthase Figure 7.7

31. Inner Mitochondrial Membrane protein based reactions  oxidation/reduction reactions release energy to make ATP viaATP synthase Figure 7.7

32. b. Steps

33. Figure 7.8

34. Build Up 1. NADH+ H+ and FADH2 drop the electrons from H to a series of re-dox proteins called cytochromes 2. As electrons move down the chain they lose energy which is used to move the H proton across the membrane to establish potential energy Harvest 1. The electrons are eventually passed to an awaiting Oxygen atom 2. The H proton moves back across the membrane through ATPSynthase and to the waiting O2 to form water 3. Conversion of energy (Potential to Kinetic) is used to form ATP

35. c. Outcomes

36. 3. Water moved out 2.NAD+ and FAD+sent back 1.ATPused

37. Summary of Aerobic Respiration

38. C. Anaerobic Respiration 1. Fermentation

39. Fermentation == onlyglycolysis

40. 2. Lactic Acid Shuttle

41. Animal cells == lactic acid shuttleand Liver

42. D. Versatility 1. Pathways

43. Figure 7.10

44. 2. Problems

45. Is random effort rewarded?