1. AP Biology Discussion Notes Tuesday 12/02/2014

2. Goals for the Day 1.Be able to write and describe the general processes of cellular respiration and why organisms do this process 2.Be able to describe the different types of Fermentation and the similarity/differences between that and aerobic respiration 3.Be prepared for lab tomorrow

3. Question of the Day Write the balanced summary equation for cellular respiration. What organisms do this process and why do they do it?

4. Part I

5. Tasmanian Devil

7. Species of the day 12/13 Tasmanian Devil Sarcophilus harrisii What is the uncontrolled growth of this Tasmanian devil’s cells called?

8. Figure 9.6-3 Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis Glucose Pyruvate Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Oxidative phosphorylation

9. Cell Respiration Following glycolysis and the citric acid cycle, NADH and FADH 2 account for most of the energy extracted from food These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation

10. Figure 9.6-3 Electrons carried via NADH Electrons carried via NADH and FADH 2 Citric acid cycle Pyruvate oxidation Acetyl CoA Glycolysis Glucose Pyruvate Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL MITOCHONDRION ATP Substrate-level phosphorylation Oxidative phosphorylation

11. Chemiosmosis: The Energy-Coupling Mechanism Electron transfer in the electron transport chain causes proteins to pump H + from the mitochondrial matrix to the intermembrane space What theory suggests Mitochondria (and chloroplasts) were once independent prokaryotes and are now symbionts with Eukaryotic cells?

12. Figure 9.15 Protein complex of electron carriers (carrying electrons from food) Electron transport chain Oxidative phosphorylation Chemiosmosis ATP synth- ase I II III IV Q Cyt c FAD FADH 2 NADH ADP  P i NAD  HH 2 H  + 1 / 2 O 2 HH HH HH 21 HH H2OH2O ATP

13. In the figure, what could we say about NADH and FADH 2 ? Are they being oxidized or reduced?

14. Figure 9.15 Protein complex of electron carriers (carrying electrons from food) Electron transport chain Oxidative phosphorylation Chemiosmosis ATP synth- ase I II III IV Q Cyt c FAD FADH 2 NADH ADP  P i NAD  HH 2 H  + 1 / 2 O 2 HH HH HH 21 HH H2OH2O ATP

15. ATP Synthase: The ATP Maker Notice the “proton” gradient! Lots of H + Inner mitochondrial membrane. ATP Synthase Matrix (inside) Little H +

16. Chemiosmosis: The Energy-Coupling Mechanism H + then moves back across the membrane, passing through the protein, ATP synthase ATP synthase uses the exergonic flow of H + to drive phosphorylation of ATP This is an example of chemiosmosis, the use of energy in a H + gradient to drive cellular work

17. Figure 9.14 INTERMEMBRANE SPACE Rotor Stator HH Internal rod Catalytic knob ADP + P i ATP MITOCHONDRIAL MATRIX

18. 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

19. 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 34% of the energy in a glucose molecule is transferred to ATP during cellular respiration, making about 32 ATP  There are several reasons why the number of ATP is not known exactly

20. Figure 9.16 Electron shuttles span membrane MITOCHONDRION 2 NADH 6 NADH 2 FADH 2 or  2 ATP  about 26 or 28 ATP Glycolysis Glucose 2 Pyruvate Pyruvate oxidation 2 Acetyl CoA Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis CYTOSOL Maximum per glucose: About 30 or 32 ATP

21. 9.5: Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen

22. Fermentation and anaerobic respiration Most cellular respiration requires O 2 to produce ATP Without O 2, the electron transport chain will cease to operate In that case, glycolysis couples with fermentation or anaerobic respiration to produce ATP

23. Anaerobic respiration uses an electron transport chain with a final electron acceptor other than O 2, for example sulfate Fermentation uses substrate-level phosphorylation instead of an electron transport chain to generate ATP Fermentation and anaerobic respiration

24. Types of Fermentation Fermentation consists of glycolysis plus reactions that regenerate NAD +, which can be reused by glycolysis Two common types are: – alcohol fermentation – lactic acid fermentation

25. In alcohol fermentation, pyruvate is converted to ethanol in two steps, with the first releasing CO 2 Alcohol fermentation by yeast is used in brewing, winemaking, and baking Alcohol Fermentation

26. 2 ADP  2 P i 2 ATP Glucose Glycolysis 2 Pyruvate 2 CO 2 2 NAD  2 NADH 2 Ethanol 2 Acetaldehyde (a) Alcohol fermentation  2 H  Figure 9.17a

27. In lactic acid fermentation, pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO 2 Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt Human muscle cells use lactic acid fermentation to generate ATP when O 2 is scarce Alcohol Fermentation

28. (b) Lactic acid fermentation 2 Lactate 2 Pyruvate 2 NADH Glucose Glycolysis 2 ADP  2 P i 2 ATP 2 NAD   2 H  Figure 9.17b

29. Similarities in Fermentation with Anaerobic and Aerobic Respiration All use glycolysis (net ATP = 2) to oxidize glucose and harvest chemical energy of food In all three, NAD + is the oxidizing agent that accepts electrons during glycolysis

30. Differences in,Anaerobic, and Aerobic Respiration The processes have different final electron acceptors: an organic molecule (such as pyruvate or acetaldehyde) in fermentation and O 2 in cellular respiration Cellular respiration produces 32 ATP per glucose molecule; fermentation produces 2 ATP per glucose molecule

31. Obligate anaerobes carry out fermentation or anaerobic respiration and cannot survive in the presence of O 2 Yeast and many bacteria are facultative anaerobes, meaning that they can survive using either fermentation or cellular respiration In a facultative anaerobe, pyruvate is a fork in the metabolic road that leads to two alternative catabolic routes Are you Obligated?

32. Figure 9.18 Glucose CYTOSOL Glycolysis Pyruvate No O 2 present: Fermentation O 2 present: Aerobic cellular respiration Ethanol, lactate, or other products Acetyl CoA MITOCHONDRION Citric acid cycle

33. Evolution & Glycolysis Ancient prokaryotes are thought to have used glycolysis long before there was oxygen in the atmosphere Very little O 2 was available in the atmosphere until about 2.7 billion years ago, so early prokaryotes likely used only glycolysis to generate ATP Glycolysis is a very ancient process

34. 9.6: 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

35. What are our major biomolecules & what are their monomers?

36. Figure 9.19 Carbohydrates Proteins Fatty acids Amino acids Sugars Fats Glycerol Glycolysis Glucose Glyceraldehyde 3- P NH 3 Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation

37. Regulation of Cellular Respiration via Feedback Mechanisms Feedback inhibition is the most common mechanism for control If ATP concentration begins to drop, respiration speeds up; when there is plenty of ATP, respiration slows down

38. Figure 9.20 Phosphofructokinase Glucose Glycolysis AMP Stimulates    Fructose 6-phosphate Fructose 1,6-bisphosphate Pyruvate Inhibits ATPCitrate Citric acid cycle Oxidative phosphorylation Acetyl CoA

39. Cell Respiration Lab Put your name on the back of the notecard Write a summary of lab procedure (of one trial) on the front (your pre-lab cheat sheet)

40. Species of the day: Yeast What will happen in this experiment? Draw out your prediction

41. Sugar water vs Plain Water Draw what you think we will see tomorrow.