1. Water behind a dam represents _____ energy. A)Kinetic B)Electrical C)Potential D)Heat E)Electromagnetic

2. The “powerhouse of the cell” is the_________. A)Nucleus. B)Mitochondrion. C)Golgi complex. D)Ribosome. E)None of these

3. Mitochondrial structure review

4. Cellular respiration provides us with the energy we use Slow-twitch muscles have more mitochondria than fast-twitch

5. Cellular Respiration

6. All Living Things Require and Consume Energy Ultimate source of energy for all life on earth is the sun We get our energy from food

7. C 6 H 12 O 6(s) + 6O 2(g)  6CO 2(g) + 6H 2 O (l) This is a combustion reaction Combustion is a kind of redox reaction Aerobic respiration of glucose is the most basic means for cells to acquire energy

8. Respiration interacts with photosynthesis in the recycling of carbon

9. Respiration at the cellular level necessitates our breathing

10. The more our cells respire, the more oxygen we need

11. Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with glucose: C 6 H 12 O 6(s) + 6O 2(g)  6CO 2(g) + 6H 2 O (l) + Energy (ATP + heat) Respiration is a REDOX reaction

12. Oxidation-Reduction Reactions Cellular respiration is a redox reaction Involves the exchange of electrons Oxidation- the loss of electrons Reduction- the gain of electrons (reduction of charge Na + Cl  Na + + Cl - Which is oxidized? Which is reduced?

13. Redox does not require complete loss or gain of electrons becomes reduced Reactants becomes oxidized becomes reduced Products Methane (reducing agent) Oxygen (oxidizing agent) Carbon dioxideWater CH 4 2 O 2 + + + CO 2 Energy 2 H 2 O

14. During cellular respiration, glucose is oxidized and oxygen is reduced C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy becomes oxidized becomes reduced

15. Electrons bound to more electronegative atoms are lower in energy The energy heirarchy of carbon bonds: CH 4 CH 3 OHCH 2 OHCOOHCO 2 Electrons in reduced molecules have higher energy than those in oxidized molecules

16. C 6 H 12 O 6(s) + 6O 2(g)  6CO 2(g) + 6H 2 O (l) The cell must control this reaction Aerobic respiration of glucose is the most basic means for cells to acquire energy

17. Oxidation is the ______, and reduction is the __________. A) gain of electrons... loss of electrons B) loss of electrons... gain of electrons C) loss of oxygen... gain of oxygen D) gain of oxygen... loss of oxygen E) gain of protons... loss of protons

18. The Stages of Cellular Respiration: A Preview Cellular respiration has three stages: –Glycolysis –The citric acid cycle (a.k.a. the Krebs cycle) –Oxidative phosphorylation (using the electron transport chain)

19. LE 9-6_1 Mitochondrion Glycolysis Pyruvate Glucose Cytosol ATP Substrate-level phosphorylation

20. LE 9-6_2 Mitochondrion Glycolysis Pyruvate Glucose Cytosol ATP Substrate-level phosphorylation ATP Substrate-level phosphorylation Citric acid cycle

21. LE 9-6_3 Mitochondrion Glycolysis Pyruvate Glucose Cytosol ATP Substrate-level phosphorylation ATP Substrate-level phosphorylation Citric acid cycle ATP Oxidative phosphorylation Oxidative phosphorylation: electron transport and chemiosmosis Electrons carried via NADH Electrons carried via NADH and FADH 2

22. Overview of respiration Glycolysis: Glucose is split, 2 pyruvates are formed, a little ATP is gained (by substrate-level phosporylation) The Citric Acid Cycle: Redox molecules NAD+ and FAD are charged up, a little ATP is gained Oxidative phosphorylation: Lots of ATP is made by ATP synthase

23. Processes important to respiration Substrate-level phosphorylation to form ATP Recycling of the Redox molecules NAD+ and FAD to carry electrons to the e- transport chain The electron transport chain, which helps generate much ATP

24. Substrate-level phosphorylation Making ATP by taking a phosphate from something and sticking it onto an ADP

25. Recycling of NAD +

26. The e - transport chain generates a proton gradient

27. Step 1: Glycolysis In: 1 glucose, 2 NAD+ Out: 2 ATP (net), 2NADH, 2 pyruvate

28. Glycolysis converts glucose to pyruvate Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate Glycolysis occurs in the cytoplasm and has two major phases: –Energy investment phase –Energy payoff phase Animation: Glycolysis Animation: Glycolysis

29. Overview of Glycolysis 10- step process Glucose (6C)  2 Pyruvate ( 3 C ea.) 2 ATPs net profit 2 NAD+’s are charged

30. LE 9-9a_1 Glucose ATP ADP Hexokinase ATP Glycolysis Oxidation phosphorylation Citric acid cycle Glucose-6-phosphate

31. LE 9-9a_2 Glucose ATP ADP Hexokinase ATP Glycolysis Oxidation phosphorylation Citric acid cycle Glucose-6-phosphate Phosphoglucoisomerase Phosphofructokinase Fructose-6-phosphate ATP ADP Fructose- 1, 6-bisphosphate Aldolase Isomerase Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate

32. LE 9-9b_1 2 NAD + Triose phosphate dehydrogenase + 2 H + NADH 2 1, 3-Bisphosphoglycerate 2 ADP 2 ATP Phosphoglycerokinase Phosphoglyceromutase 2-Phosphoglycerate 3-Phosphoglycerate

33. LE 9-9b_2 2 NAD + Triose phosphate dehydrogenase + 2 H + NADH 2 1, 3-Bisphosphoglycerate 2 ADP 2 ATP Phosphoglycerokinase Phosphoglyceromutase 2-Phosphoglycerate 3-Phosphoglycerate 2 ADP 2 ATP Pyruvate kinase 2 H 2 O Enolase Phosphoenolpyruvate Pyruvate

34. Energetics of Glycolysis

35. Concept 9.3: The citric acid cycle completes the energy- yielding oxidation of organic molecules Before the citric acid cycle can begin, pyruvate must be converted to acetyl CoA, which links the cycle to glycolysis

36. Before the citric acid cycle, pyruvate is fastened to Co-Enzyme A

37. Step 2: Citric Acid cycle In: Acetyl CoA, NAD+, FAD, ADP Out: CO 2, NADH, FADH, some ATP

38. In the citric acid cycle, electrons are ripped from carbon onto the redox molecules NAD+ and FAD All carbon is converted to CO2 A little bit of ATP is generated

39. The citric acid cycle, also called the Krebs cycle, takes place within the mitochondrial matrix The cycle oxidizes organic fuel derived from pyruvate, generating one ATP, 3 NADH, and 1 FADH 2 per turn The citric acid cycle has eight steps, each catalyzed by a specific enzyme

40. LE 9-11 Pyruvate (from glycolysis, 2 molecules per glucose) ATP Glycolysis Oxidation phosphorylation Citric acid cycle NAD + NADH + H + CO 2 CoA Acetyl CoA CoA Citric acid cycle CO 2 2 3 NAD + + 3 H + NADH3 ATP ADP + P i FADH 2 FAD

41. LE 9-12_4 ATP Glycolysis Oxidation phosphorylation Citric acid cycle Citric acid cycle Citrate Isocitrate Oxaloacetate Acetyl CoA H2OH2O CO2CO2 NAD + NADH + H +  -Ketoglutarate CO2CO2 NAD + NADH + H + Succinyl CoA Succinate GTP GDP ADP ATP FAD FADH 2 P i Fumarate H2OH2O Malate NAD + NADH + H +

42. Step 3: Oxidative Phosphorylation In which the electron transport chain generates a proton gradient, and ATP synthase makes tons of ATP

43. Oxidative phosphorylation Electron-carrying redox molecules (NADH and FADH 2 ) transfer their electrons to the e- transport chain The e- transport chain uses the electrons to create a proton gradient across the inner mitochondrial membrane ATP synthase uses the potential energy in the proton gradient to convert much ADP into ATP

44. LE 9-13 ATP Glycolysis Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle NADH 50 FADH 2 40 FMN FeS I FAD FeS II III Q FeS Cyt b 30 20 Cyt c Cyt c 1 Cyt a Cyt a 3 IV 10 0 Multiprotein complexes Free energy (G) relative to O2 (kcal/mol) H2OH2O O2O2 2 H + + 1 / 2

45. The electron transport chain uses electrons to generate a proton gradient Intermembrane space Inner mitochondrial membrane Mitochondrial matrix Protein complex Electron carrier Electron flow NADH NAD  FADFADH 2 HH HH HH HH H2OH2O HH HH ATP synthase 2  O2O2 1212 HH P  ADPATP Electron Transport Chain Chemiosmosis O XIDATIVE P HOSPHORYLATION HH HH HH HH HH HH HH

46. Some poisons can disrupt e- transport

47. The energy stored in a H + gradient across a membrane couples the redox reactions of the electron transport chain to ATP synthesis The H + gradient is referred to as a proton- motive force, emphasizing its capacity to do work Animation: Fermentation Overview Animation: Fermentation Overview

48. LE 9-14 INTERMEMBRANE SPACE H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ATP MITOCHONDRAL MATRIX ADP + P i A rotor within the membrane spins as shown when H + flows past it down the H + gradient. A stator anchored in the membrane holds the knob stationary. A rod (or “stalk”) extending into the knob also spins, activating catalytic sites in the knob. Three catalytic sites in the stationary knob join inorganic phosphate to ADP to make ATP.

49. An Accounting of ATP Production by Cellular Respiration During cellular respiration, most energy flows in this sequence: glucose  NADH  electron transport chain  proton-motive force  ATP About 40% of the energy in a glucose molecule is transferred to ATP during cellular respiration, making about 38 ATP

50. LE 9-16 CYTOSOL Electron shuttles span membrane 2 NADH or 2 FADH 2 MITOCHONDRION Oxidative phosphorylation: electron transport and chemiosmosis 2 FADH 2 2 NADH6 NADH Citric acid cycle 2 Acetyl CoA 2 NADH Glycolysis Glucose 2 Pyruvate + 2 ATP by substrate-level phosphorylation + 2 ATP by substrate-level phosphorylation + about 32 or 34 ATP by oxidation phosphorylation, depending on which shuttle transports electrons form NADH in cytosol About 36 or 38 ATP Maximum per glucose:

51. During cellular respiration, NADH A) is converted to NAD + by an enzyme called dehydrogenase. B) is chemically converted into ATP. C) is reduced to form NAD +. D) delivers its electron load to the electron transport chain. E) None of the choices are correct.

52. Oxygen is the final e- resting place in the chain

53. Human cells can do glycolysis faster than human lungs can take in oxygen

54. Q: What happens if there is not enough oxygen?

55. A: It depends on what kind of creature you are…

56. Without O2, yeast make alcohol

58. Humans make lactic acid instead of ethanol

59. Lactic Acid in muscles creates a burning sensation Overworked muscles can become anoxic In low oxygen environments, pyruvate is converted to lactate to regenerate NAD+ Lactic acid causes great suffering

60. LE 9-17a CO 2 + 2 H + 2 NADH2 NAD + 2 Acetaldehyde 2 ATP 2 ADP + 2 P i 2 Pyruvate 2 2 Ethanol Alcohol fermentation Glucose Glycolysis

61. LE 9-17b CO 2 + 2 H + 2 NADH2 NAD + 2 ATP 2 ADP + 2 P i 2 Pyruvate 2 2 Lactate Lactic acid fermentation Glucose Glycolysis

62. Fermentation and Cellular Respiration Compared Both processes use glycolysis to oxidize glucose and other organic fuels to pyruvate The processes have different final electron acceptors: an organic molecule (such as pyruvate) in fermentation and O 2 in cellular respiration Cellular respiration produces much more ATP

63. LE 9-18 Pyruvate Glucose CYTOSOL No O 2 present Fermentation Ethanol or lactate Acetyl CoA MITOCHONDRION O 2 present Cellular respiration Citric acid cycle

64. The Evolutionary Significance of Glycolysis Glycolysis occurs in nearly all organisms Glycolysis probably evolved in ancient prokaryotes before there was oxygen in the atmosphere

65. Glycolysis and the citric acid cycle connect to many other metabolic pathways Gycolysis and the citric acid cycle are major intersections to various catabolic and anabolic pathways

67. Metabolism can build up, or break down

68. LE 6-15 ATP needed to drive biosynthesis ATP CITRIC ACID CYCLE Acetyl CoA Amino groups Proteins Amino acidsFatty acidsGlycerol Fats Cells, tissues, organisms Carbohydrates Sugars GLUCOSE SYNTHESIS PyruvateG3PGlucose

69. The Versatility of Catabolism Catabolic pathways funnel electrons from many kinds of organic molecules into cellular respiration Glucose- 4 calories/gram Proteins- 4 calories/gram Fats- 9 calories/gram

70. Which of the following processes produces the most ATP per molecule of glucose oxidized? A) aerobic respiration B) anaerobic respiration C) alcoholic fermentation D) lactic acid fermentation E) All produce approximately the same amount of ATP per molecule of glucose