1. Today is Monday, November 10 th, 2014 Pre-Class: Take a deep breath in and out. No, that’s not respiration…that’s ventilation. Still, why do we need oxygen? Exactly what does it do for us? Also: How do you do? In This Lesson: Cellular Respiration (Lesson 2 of 3)

2. Today’s Agenda Respiration – Aerobic Glycolysis Pyruvate Oxidation Citric Acid Cycle Oxidative Phosphorylation – Anaerobic Fermentation (Alcohol/Lactic Acid) Where is this in my book? – Chapter 9.

3. By the end of this lesson… You should be able to describe the aerobic and anaerobic respiration pathways by their inputs and outputs. You should know where the cell gets its ATP. You should be able to relate the mitochondrion’s structure with its function.

4. So what is it? Think of cellular respiration like a harvest of chemical energy. – Like Thanksgiving all the time. This is where cells actually use the energy they have available to them to accomplish work. The goal? – PRODUCE ATP.

5. Cell “Work” Active Transport

6. Cell “Work” Movement of Proteins and Molecules

7. Cell “Work” Phosphorylation and Molecule Activation, Building Molecules

8. And ATP is…? You know how you can use money for all kinds of things? Money just facilitates some other activity? And you need it in the right form for your country? – The same goes for ATP. It’s used all over the place. – Glucose is like a foreign currency. It needs to be exchanged. ATP is Adenosine Triphosphate. – It’s a modified nucleotide with 3 phosphates instead of 1. ATP = Adenine + Ribose + 3 Phosphate Groups ADP = Adenine + Ribose + 2 Phosphate Groups AMP = Adenine + Ribose + 1 Phosphate Group – Adding phosphates is endergonic and requires energy. – Removing them is exergonic and absorbs energy.

9. ATP What I’d like you to think about when you hear “ATP” is a giant chocolate bar: http://savingmoneyplan.com/wp-content/uploads/2012/11/hersheys.jpg ATP

10. Chocolate Chocolate is high in Calories. – Therefore it’s got a lot of energy. Chocolate is high in sugar. – It provides you with a boost when you eat it. Chocolate bars often are divided into squares or rectangles that you can eat one-at-a-time. – You don’t need to destroy the whole bar to get something out of it.

11. ATP ATP has high-energy bonds. – Your cell breaks off a phosphate and replaces those bonds with lower-energy bonds. ATP provides free energy when hydrolyzed and gains free energy. ATP can be reused. – Like putting a square back on the chocolate bar. I wish I could do that.

12. Can chocolate be re-used?

13. Anyway… How does ATP actually store energy? – Each phosphate group added to the adenosine molecule becomes progressively harder to “hold.” Remember, they have a -1 or -2 charge, so that’s a lot of negativity built up. – The phosphates can “pop off” easily and release energy. – This makes ATP a great energy donor. O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - Energy

14. ATP

15. -OH Anyway… How does ATP transfer energy? The hydrolysis of ATP to ADP releases energy. ΔG = -7.3 kcal/mol Key: The “missing” phosphate is replaced by a hydroxide from water. Key: The formation of this bond releases energy. Key: The other hydrogen ion (from water) goes to the phosphate. O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - O – P – O O - H-

16. The Catch As great as ATP is for energy transfer, it’s a particularly bad molecule for energy storage. – It’s quite unstable and transfer its phosphate group too easily. A working muscle recycles over 10,000,000 ATP molecules every second.

17. ATP Production One energy source for production of ATP is the enzyme/channel protein ATP Synthase. – Located in the mitochondrial membrane. H + ions flow down the channel protein and power the enzyme like a hydroelectric dam. – The question is…how do we turn it on? H+H+ catalytic head rod rotor H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ADP P + ATP

18. Inquiry Break Cellular Respiration – An Overview POGIL Go to the second STOP sign. IMPORTANT: The POGIL shows the “link reaction” – more on that later – as occurring in the intermembrane space. It doesn’t – it occurs in the matrix.

19. Back to “harvesting energy…” You should know the familiar equation for respiration: – C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ATP [glucose] + [oxygen]  [carbon dioxide] + [water] + [energy] Before we really explore this in depth, keep something in mind: – Respiration is, almost literally, burning calories. – It’s like burning a piece of wood, only it happens in a lot of little steps instead of one big one. It even gives off heat, just not as much.

20. Respiration: Big Ideas As big molecules are broken into smaller ones… …bonds are broken… …and electrons are moved from one molecule to another… …“carrying energy” with them, which is: – Stored in a new bond OR – Released as heat OR – Harvested to make ATP.

21. Respiration: Big Ideas Therefore, quite a bit of respiration is made of redox (reduction/oxidation) reactions. Key: Reduction is a gain of electrons; oxidation is a loss of electrons. Key: The oxidized atom is the reducing agent and vice versa. Key: Remember that with “OIL RIG:” – “Oxidation Is Loss” – “Reduction Is Gain” + + + + e-e- - - e-e- Loss of e - Gain of e - Oxidized Reduced Reducing Agent Oxidizing Agent

22. Respiration: Big Ideas In living systems, electrons are moved with hydrogen atoms. – Key: When you see H moving, you’re seeing electrons move too. Consider the overall respiration equation: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ATP The oxygen has gained hydrogens. Reduction Oxidation The glucose will lose hydrogens.

23. Oxidation and Reduction Oxidation: – Removing H – Loss of electrons – Release of energy – Exergonic Reduction: – Adding H – Gain of electrons – Storage of energy – Endergonic

24. Coupling Reactions I’m sure you remember that exergonic and endergonic reactions are coupled. – The energy released by the exergonic reaction is harnessed for use in an endergonic reaction. C-C bonds are broken, but more importantly… Key: C-H bonds are broken to strip off H atoms. – C 6 H 12 O 6  CO 2 = oxidation of glucose fuel. – O 2  H 2 O = reduction of oxygen. Electrons are attracted to the more electronegative atom, which liberates potential atom. – In chemistry, F is the most electronegative, but it’s too strong for living systems. O is the most electronegative for biology. Which partly explains why fluoride ions are good in toothpaste.

25. Okay, let’s go… We’re ready to start learning the details of the respiration “story.” We’ll begin with two important “characters:” – NAD + Nicotinamide adenine dinucleotide, AKA niacin or Vitamin B 3 – FAD Flavin adenine dinucleotide, AKA riboflavin or Vitamin B 2 Key: These are each electron carriers and are responsible for moving H atoms around. I want you to think of these each as batteries.

26. Electron Carriers/Batteries Oxidized: NAD + and FAD are the “drained” batteries: Reduced: NADH and FADH 2 are the “charged” batteries: I’ll be using these symbols throughout the lesson.

27. A Closer Look at NAD + and NADH http://www.uic.edu/classes/bios/bios100/lectures/NADH01.jpg

28. Cellular Respiration Overview Aerobic Respiration 1.Glycolysis 2.Pyruvate Oxidation 3.Krebs/Citric Acid Cycle 4.Oxidative Phosphorylation Note: If oxygen is not around, many cells carry out fermentation following glycolysis. Cytosol Mitochondria

29. Warm-Up CrashCourse – ATP and Respiration – Part 1

30. Inquiry Break Cellular Respiration – An Overview POGIL Stop at the end of Page 4.

31. Quick Reminder: Mitochondrial Structure They have two bilayer membranes. From the outside in: – Outer membrane – Intermembrane space – Inner membrane – Matrix The inner membrane has folds called cristae. Sketch it like you mean it. http://course1.winona.edu/kbates/Bio241/images/figure-04-14.jpg

32. Glycolysis The name “glycolysis” literally means “splitting sugar.” In this process, glucose (6 carbons) is broken down into two pyruvate molecules (3 carbons). Key: It’s inefficient: 1 glucose molecule results in only 2 net ATP. – The pyruvates can be broken down further for more energy. Glycolysis takes place in the cytosol. Why? – Energy is needed by all cells, prokaryotic or eukaryotic, so it had to have evolved a long time ago, before eukaryotes.

33. Glycolysis: Evolution Because early cells had no organelles, and because the early atmosphere had no oxygen, life had to find a way to produce ATP anaerobically in the cytosol. – Side note: “Cytoplasm” technically extends into the mitochondria, chloroplasts, and other organelles. Cytosol is the cytoplasm minus the organelles. Since all cells evolved from these early ones, glycolysis is like a homologous “structure” to us all.

34. Glycolysis: Input/Output Glycolysis is actually made up of ten (really 9.5) smaller reactions. Before we explore them, let’s get the input and output straight: – Input Glucose (1) ATP (2) – Output Pyruvate (2) ATP (4 total, 2 net) NADH (2)

35. The Detailed View I do not need you to memorize this. However, it’s useful to see the pathway in full at least once to: – see why the input/output is so. – appreciate what’s happening. For clarity, enzymes are shown in italics and inputs/outputs are underlined. You are responsible for the inputs and outputs.

36. Glycolysis: Reactions [Detailed] 1.Hexokinase dephosphorylates ATP and adds the phosphate to glucose, creating glucose 6-phosphate. This also prevents glucose from exiting the cell. – -1 Glucose – -1 ATP 2.Phosphoglucoisomerase converts glucose 6-phosphate to fructose 6-phosphate through a shape change. 3.Phosphofructokinase dephosphorylates ATP and adds the phosphate to fructose 6-phosphate, creating fructose 1,6-bisphosphate. – -1 ATP

37. Glycolysis: Reactions [Detailed] 4.Aldolase converts fructose 1,6-bisphosphate into glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). – Isomerase converts the DHAP to G3P as well. – This means there are two G3P molecules and two of every molecule moving forward. 5.NAD + oxidizes G3P and then triose phosphate dehydrogenase adds an inorganic phosphate group to it, creating 1,3-bisphosphoglycerate (1,3-BPG). – +2 NADH 6.Phosphoglycerokinase removes the phosphate and phosphorylates ADP, creating 3-phosphoglycerate. – +2 ATP

38. Glycolysis: Reactions [Detailed] 7.Phosphoglyceromutase moves a phosphate group, creating 2-phosphoglycerate. – Underachiever. 8.Enolase adds a double bond within the compound, creating phosphoenopyruvate (PEP). 9.Pyruvate kinase removes a phosphate group and phosphorylates ADP, creating pyruvate. – +2 ATP – +2 pyruvate

39. Glycolysis http://cerebraldopamine.files.wordpress.com/2011/09/glycolysis_pathway.jpg

40. Quick Note I know I said you didn’t need to know the details of glycolysis, but it’s probably worth remembering G3P. It’s a 3-carbon sugar that will come up again in photosynthesis.

41. Pyruvate Oxidation: Input/Output Prior to entering the Citric Acid Cycle, pyruvate has to be oxidized. – Your book calls it “pyruvate oxidation” but it is also known as the “link reaction” (especially by the POGIL). As usual, just know the inputs/outputs: – Input Pyruvate (2) – Output Acetyl CoA (2) NADH (2) CO 2 (2) [waste]

42. Pyruvate Oxidation: Reactions [Detailed] First, the two charged pyruvate molecules enter the mitochondrion via active transport. – Both pyruvate oxidation and the citric acid cycle take place in the matrix (inside the inner membrane). Enzyme complex pyruvate dehydrogenase complex: – Removes CO 2, making acetate. (6 carbon glucose to 3 carbon pyruvate to 2 carbon fragment now) -2 Pyruvate +2 CO 2 [waste] – Oxidizes it and reduces NAD + to NADH. +2 NADH – Adds Coenzyme A (sulfur-containing compound from a B vitamin), making acetyl CoA. +2 acetyl CoA Matrix  

43. Pyruvate Oxidation http://schoolworkhelper.net/wp-content/uploads/2011/02/pyruvate-oxidation.jpg

44. Citric Acid Cycle: Input/Output The products of pyruvate oxidation (acetyl CoA) feed the Citric Acid Cycle, also known as the Krebs Cycle. The Citric Acid Cycle is made of eight reactions but “turns” twice for each acetyl CoA input. Importantly, it is a cycle, meaning that it is continuously running like a revolving door. For both turns: – Input Acetyl CoA (2) – Output ATP (2) NADH (6) FADH 2 (2) CO 2 (4) [waste]

45. Citric Acid Cycle: Reactions [Detailed] 1.Acetyl CoA loses its acetyl group to oxaloacetate, forming citrate. – Hence the name of the cycle (citrate is ionized citric acid). – -2 Acetyl CoA after both turns. 2.Citrate is made into isocitrate (isomer) by removing a water molecule and then adding one. 3.Isocitrate is oxidized by NAD + and the resulting compound loses a CO 2, becoming α-ketoglutarate. – +2 NADH after both turns. – +2 CO 2 after both turns. 4.α-ketoglutarate loses another CO 2 and is then oxidized by NAD +, forming succinyl CoA. – +2 NADH after both turns. – +2 CO 2 after both turns.

46. Citric Acid Cycle: Reactions [Detailed] 5.CoA (in succinyl CoA) is replaced by a phosphate group which is then transferred to GDP (making GTP), which then is dephosphorylated as ADP becomes ATP. Meanwhile, succinyl CoA has become succinate. – +2 ATP after both turns. 6.Succinate is oxidized twice by FAD, making fumarate. – +2 FADH 2 after both turns. 7.Water rearranges bonds in fumarate, making malate. 8.Malate is oxidized by NAD +, making oxaloacetate. The cycle can repeat as an acetyl group comes from another acetyl CoA. – +2 NADH after both turns.

47. Citric Acid Cycle http://www.bio.miami.edu/tom/courses/protected/MCB6/ch12/12-10.jpg

48. So… How’s it going? I know, phew, right? Um… Well how’s your family? Good, good. Uh… Okay let’s just…let’s just keep going…

49. Review We’re about to go to the next step, but let’s recap a little bit. – Cue marker joke. – “Recap”…get it? From one glucose molecule: – 6 CO 2 [waste] – 4 ATP (net) – And…importantly…?

50. Review We have also built up: – 10 NADH – 2 FADH 2 All of that effort (charging the batteries) is now about to pay off. Cue oxidative phosphorylation. http://fc08.deviantart.net/fs25/f/2008/092/5/f/IMA_FIRIN_MAH_LAZOR_by_Teh_Kenji.gif

51. Oxidative Phosphorylation Oxidative phosphorylation is technically broken into two phases: – Electron Transport Chain Produces none of the ATP. – Chemiosmosis Produces all of the ATP.

52. Oxidative Phosphorylation Electron Transport Chain All throughout this process, ΔG has been mostly positive, meaning our products to this point are high potential energy and are set to “fall” back down to lower energy. The cell will allow this to happen in short stages. – Not falling off a building…more like falling down stairs. This is called electron transport chain (ETC) and it takes place primarily within the inner membrane of the mitochondrion. – Remember, the inner membrane has lots of folds called cristae that add surface area and make this even more efficient.

53. Electron Transport Chain: Reactions [Detailed] 1.NADH gives up two electrons to Enzyme Complex I: – First to FMN (flavin mononucleotide), then to Fe-S, an iron- sulfur protein. – Complex I is an integral membrane protein called NADH Reductase. – NADH  NAD + + H + + 2 e - (remember that H + ) OR 1.FADH 2 gives up two electrons to Enzyme Complex II: – Directly to Fe-S. – Complex II, stuck to the inside of the membrane like a G protein, is called succinate dehydrogenase. – FADH 2  FAD + 2 H + + 2 e - (remember those 2 H + )

54. Electron Transport Chain: Reactions [Detailed] 2.Next, the Fe-S passes the electrons to ubiquinone (abbreviated Q, also known as Coenzyme Q or CoQ). – Ubiquinone is not a protein and is hydrophobic, so it moves around within the inner membrane. 3.Ubiquinone passes its electrons to Enzyme Complex III, called cytochrome reductase: – First to Cytochrome b (abbreviated Cyt b)… – …then to another Fe-S protein… – …then to Cyt c 1 …

55. Electron Transport Chain: Reactions [Detailed] 4.Complex III (specifically Cyt c 1 ) then passes its electrons to Cyt c, which passes its electrons to Enzyme Complex IV, called cytochrome oxidase: – First to Cyt a… – …then to Cyt a 3. 5.Now, at the end of our giant microscopic hot potato party, Cyt a 3 passes its electrons to oxygen, the final electron acceptor. – Oxygen picks up a -2 charge, then two protons, making H 2 O. – Oxygen plays this role because it is quite electronegative. The electron transport chain has ended, but in the process we’ve liberated a buttload of potential energy. – And we have to pee, since we’ve also generated some water.

56. Oxidative Phosphorylation http://www.tokresource.org/tok_classes/biobiobio/biomenu/cell_respiration/c8_9x16_chemiosmosis.jpg

57. Electron Transport Chain: The Catch The catch: We haven’t made any ATP. – “Huhwhat?” The cell instead puts that liberated energy to use engaging in something called chemiosmosis: – Making an H + (proton) gradient across a membrane, in this case the mitochondrial membrane, to drive work.

58. Oxidative Phosphorylaton: Chemiosmosis Enzyme complexes I, III, and IV all pump hydrogen ions out of the mitochondrial matrix. This creates an electrochemical gradient: – The intermembrane space now has a buildup both of protons and of positive charge. In a specialized form of facilitated diffusion, the cell lets these protons diffuse back into the matrix through ATP Synthase. – ATP Synthase is a membrane protein/enzyme complex. – As protons diffuse, part of the protein spins (yes, spins), activating sites that generate ATP from ADP.

59. ATP Synthase H+H+ catalytic head rod rotor H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ ADP P + ATP http://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Atp_s ynthase.PNG/300px-Atp_synthase.PNG

60. ATP Synthase ATP Synthase provides protons the only way back into the cristae. Think of the enzyme much like a waterwheel: – The water (proton stream) turns the wheel (ATP Synthase’s rotor), generating power (ATP).

61. Oxidative vs. Substrate-Level Phosphorylation Notice something. We have now seen ATP generated both by an enzyme transferring a phosphate from another molecule, or through ATP Synthase putting ADP and P i together. Biochemists distinguish these as follows: – Transferring P from another molecule = substrate- level phosphorylation. Krebs Cycle/Glycolysis – Adding P i through chemiosmosis = oxidative phosphorylation. Chemiosmosis

62. Oxidative Phosphorylation: Input/Output After all this, we can look at oxidative phosphorylation’s inputs and outputs: – Input NADH 10 FADH 2 (2) O 2 (6) – Output ATP! (realistically 26-28 per glucose, though some sources say upwards of 34 per glucose. Unlikely.) H 2 O (4) [waste] NAD + FAD

63. Did you notice something? Glycolysis is an anaerobic step. Pyruvate oxidation and the citric acid cycle don’t use oxygen directly. HOWEVER! Because they precede the ETC, they will not run without oxygen. – Only the ETC actually needs oxygen.

64. Cell Respiration Summary C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ATP Reactants: – 1 C 6 H 12 O 6 1 used in Glycolysis – 6 O 2 6 used in Oxidative Phosphorylation Products: – 6 CO 2 2 from Pyruvate Oxidation 4 from Citric Acid Cycle – 6 H 2 O 6 from Oxidative Phosphorylation – 30 or 32 ATP [maximum] 2 (net) from Glycolysis 2 from Citric Acid Cycle 26 or 28 from Oxidative Phosphorylation

65. Cell Respiration Summary C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O Oxidative Phosphorylation Glycolysis and Oxidative Phosphorylation Glycolysis Pyruvate Oxidation and Citric Acid Cycle Pyruvate Oxidation and Citric Acid Cycle

66. Closure Just kidding! We’re not done yet.

67. Inquiry Break Cellular Respiration – An Overview POGIL Stop at the end of Page 5 (STOP sign).

68. In a world… …without oxygen, like the world in which glycolysis originally evolved, there’s an issue: – We can’t run oxidative phosphorylation, so the Krebs Cycle also doesn’t move. – Alternatively, if you’re a prokaryote, you don’t have mitochondria, so that’s out too. Furthermore, glycolysis is not a cycle: – Input Glucose (1) ATP (2) – Output Pyruvate (2) ATP (4 total, 2 net) NADH (2)

69. Problems and Solutions The Problems: 1.We don’t have oxygen around for the end of the electron transport chain. 2.NAD + is ultimately responsible for creating ATP as it oxidizes G3P. It needs to be restored from NADH. The Solutions: 1.Use a different molecule, like something with sulfur, to accept electrons. If so, this is anaerobic respiration. In anaerobic respiration, pyruvate oxidation and citric acid cycle occur in the cytosol, while the membrane used for oxidative phosphorylation is the cell membrane. Pretty cool. 2.Recycle NADH into NAD + through fermentation.

70. Fermentation Two types of fermentation: – Alcohol fermentation oxidizes NADH through the production of ethanol and CO 2. Utilized by bacteria and yeast (fungus). This explains winemaking, brewing, and bubbles in pizzas/bread. – Yeast farts! – Lactic acid fermentation oxidizes NADH through the production of…lactic acid. Utilized by fungi, bacteria, and animals. This explains cheese, yogurt, and not why your muscles are sore the next day after exercise.

71. Aside: Alcohol Fermentation in Nature BBC – Alcoholic Vervet Monkeys

72. Aside: Lactic Acid You may have heard that lactic acid leads to muscle soreness. Upon resumption of aerobic respiration, your muscles clear the lactic acid relatively quickly. – So it’s not lactic acid. Some research suggests that short-term soreness is due to K + ions, while longer-term soreness is due to micro-tears in muscle fiber.

73. Back to Fermentation Important stuff to note: – Fermentation creates no ATP on its own but allows glycolysis to continue. – Because the fermentation pathway yields only 2 net ATP, it’s inefficient for multicellular organisms. – Obligate anaerobes (prokaryotes that don’t use oxygen) utilize fermentation regularly, but they’re single-celled. – Facultative anaerobes (use oxygen only when available) utilize fermentation regularly as well. – Humans and other eukaryotes mainly use it as backup for when the blood can’t deliver enough O 2. Aside: Brain cells can’t really do it. Strokes = dangerous.

74. Aside: Athletes So here’s a question for you – biomechanically, how do athletes have higher endurance than non-athletes? The answer, in part, appears to be efficiency of oxygen use. – Athletes simply get more oxygen dissolved into their blood compared to the same volume breath from a non-athlete. – This explains why “altitude training” helps make respiratory pathways even more efficient.

75. Warm-Up CrashCourse – ATP and Respiration – Part 2

76. Pseudo-Closure Whisper Down the Metabolic Pathway I have written a short paragraph on respiration, but I’ve broken it into 31 “cards.” – So each card has a fragment of a sentence or two. Your job, when you receive your card(s), is to arrange yourself in order with everyone else’s. – You have to hold onto your card, so get in line. This is challenging. Hints: – First figure out what yours is talking about. – Then think of what comes before and after it – go find those people first. – If you’re the beginning or end, tell people so.

77. Last Topic: Versatility Glycolysis accepts a lot of inputs; it doesn’t need to be glucose. – Other molecules like starch just get broken down to glucose first. Proteins are not efficient sources of energy. – But when they are used, they must be hydrolyzed back to amino acids. – The amino group becomes waste (ammonia, urea, or uric acid – it goes in yo’ pee). – The carboxyl group and central carbon become a 2-carbon sugar and is passed into respiration.

78. Last Topic: Versatility Triglycerides – great energy source that they are – have an interesting way of getting into the respiration pathway. The glycerol head enters the glycolysis pathway as G3P. The fatty acid tails are broken into 2-carbon fatty acids and enter the citric acid cycle as acetyl CoA. – Given that only two acetyl CoAs enter for each glucose, one triglyceride provides a heck of a lot of “bang for your bond.”

79. Versatility: Fats and Carbs Fats generate 2x the ATP compared to carbohydrates. – They contain a lot of carbon atoms that are partially oxidized already. On the other hand, carbohydrates are faster to use. – They contain oxygen atoms that are partially oxidized already. – Less energy released than from fats, though.

80. Inquiry Break Cellular Respiration – An Overview POGIL “Finish him!”…I mean…“it.”

81. Cell Respiration Summary Glycolysis Pyruvate Oxidation Citric Acid Cycle Oxidative Phosphorylation Fermentation Pyruvate Oxidation Oxygen Mitochondrial Matrix Cytosol No Oxygen O S Citric Acid Cycle Oxidative Phosphorylation

82. Real Closure Keep in mind that actual people are behind these myriad facts. For example: http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1978/mitchell.jpg Peter Mitchell Chemiosmosis http://media-2.web.britannica.com/eb-media/43/21043-004-D206E5D2.jpg Hans Krebs Citric Acid Cycle You? ?

83. Surprise! Oxidative Phosphorylation POGIL