Cellular Respiration and Fermentation 7 Cellular Respiration and Fermentation

© 2014 Pearson Education, Inc.

Light energy ECOSYSTEM Photosynthesis in chloroplasts Organic Figure 7.2 Light energy ECOSYSTEM Photosynthesis in chloroplasts Organic molecules CO2  H2O  O2 Cellular respiration in mitochondria Figure 7.2 Energy flow and chemical recycling in ecosystems ATP powers most cellular work ATP Heat energy 3

Concept 7.1: Catabolic pathways yield energy by oxidizing organic fuels __________________________________________________ _________________________________________ ___________________________________________________________________________ © 2014 Pearson Education, Inc. 4

________________________________________ ________________________________________________________________________________ Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the sugar glucose ________________________________________ © 2014 Pearson Education, Inc. 5

The Principle of Redox _________________________________________________________________________ _______________________________ © 2014 Pearson Education, Inc. 6

becomes oxidized (loses electron) becomes reduced (gains electron) Figure 7.UN01 becomes oxidized (loses electron) becomes reduced (gains electron) Figure 7.UN01 In-text figure, NaCl redox reaction, p. 136 7

becomes oxidized becomes reduced Figure 7.UN03 becomes oxidized becomes reduced Figure 7.UN03 In-text figure, cellular respiration redox reaction, p. 137 8

Stepwise Energy Harvest via NAD+ and the Electron Transport Chain _____ ______________ __________ ______________________________________________________________________ © 2014 Pearson Education, Inc. 9

2 e− 2 H 2 e−  H NAD NADH H Dehydrogenase Reduction of NAD Figure 7.4 2 e− 2 H 2 e−  H NAD NADH H Dehydrogenase Reduction of NAD  2[H] (from food)  H Oxidation of NADH Nicotinamide (reduced form) Nicotinamide (oxidized form) Figure 7.4 NAD+ as an electron shuttle 10

(a) Uncontrolled reaction (b) Cellular respiration Figure 7.5 ½ ½ H2  O2 2 H  O2 Controlled release of energy 2 H  2 e− ATP ATP Explosive release Electron transport chain Free energy, G Free energy, G ATP 2 e− Figure 7.5 An introduction to electron transport chains ½ O2 2 H H2O H2O (a) Uncontrolled reaction (b) Cellular respiration 11

The Stages of Cellular Respiration: A Preview __________________________________________________________________________ ____________________________________________________________ _____________________ _________________ Animation: Cellular Respiration © 2014 Pearson Education, Inc. 12

Electrons via NADH and FADH2 Electrons via NADH Oxidative Figure 7.6-3 Electrons via NADH and FADH2 Electrons via NADH Oxidative phosphorylation: electron transport and chemiosmosis Pyruvate oxidation Glycolysis Citric acid cycle Glucose Pyruvate Acetyl CoA CYTOSOL MITOCHONDRION Figure 7.6-3 An overview of cellular respiration (step 3) ATP ATP ATP Substrate-level Substrate-level Oxidative 13

Concept 7.2: Glycolysis harvests chemical energy by oxidizing glucose to pyruvate _________________________________ __________________________ ____________________ _________________ ____________________________ © 2014 Pearson Education, Inc. 14

Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Figure 7.UN06 Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Glycolysis Figure 7.UN06 In-text figure, mini-map, glycolysis, p. 140 ATP ATP ATP 15

Energy Investment Phase Figure 7.8 Energy Investment Phase Glucose 2 ADP  2 P 2 ATP used Energy Payoff Phase 4 ADP  4 P 4 ATP formed 2 NAD  4 e−  4 H 2 NADH  2 H Figure 7.8 The energy input and output of glycolysis 2 Pyruvate  2 H2O Net Glucose 2 Pyruvate  2 H2O 4 ATP formed − 2 ATP used 2 ATP 2 NAD  4 e−  4 H 2 NADH  2 H 16

Glycolysis: Energy Investment Phase Figure 7.9a Glycolysis: Energy Investment Phase Glyceraldehyde 3-phosphate (G3P) ATP Glucose 6-phosphate Fructose 6-phosphate ATP Fructose 1,6-bisphosphate Glucose ADP ADP Isomerase 5 Hexokinase Phosphogluco- isomerase Phospho- fructokinase Aldolase Dihydroxyacetone phosphate (DHAP) 1 4 2 3 Figure 7.9a A closer look at glycolysis (part 1: investment phase) 17

Glycolysis: Energy Investment Phase Figure 7.9aa-3 Glycolysis: Energy Investment Phase ATP Glucose 6-phosphate Fructose 6-phosphate Glucose ADP Hexokinase Phosphogluco- isomerase 1 Figure 7.9aa-3 A closer look at glycolysis (part 1a, step 3) 2 18

Glycolysis: Energy Investment Phase Figure 7.9ab-3 Glycolysis: Energy Investment Phase Glyceraldehyde 3-phosphate (G3P) Fructose 6-phosphate Fructose 1,6-bisphosphate ATP ADP Isomerase 5 Phospho- fructokinase Aldolase Dihydroxyacetone phosphate (DHAP) 4 Figure 7.9ab-3 A closer look at glycolysis (part 1b, step 3) 3 19

Glycolysis: Energy Payoff Phase Figure 7.9b Glycolysis: Energy Payoff Phase 2 ATP 2 ATP 2 NADH 2 H2O Glyceraldehyde 3-phosphate (G3P) 2 ADP 2 NAD  2 H 2 ADP 2 2 2 2 2 Triose phosphate dehydrogenase Phospho- glycerokinase Phospho- glyceromutase Enolase Pyruvate kinase 2 P i 9 1,3-Bisphospho- glycerate 7 3-Phospho- glycerate 8 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) 10 Pyruvate 6 Figure 7.9b A closer look at glycolysis (part 2: payoff phase) 20

Glycolysis: Energy Payoff Phase Figure 7.9ba-3 Glycolysis: Energy Payoff Phase 2 ATP 2 NADH Glyceraldehyde 3-phosphate (G3P) 2 NAD  2 H 2 ADP 2 2 Triose phosphate dehydrogenase Phospho- glycerokinase 2 P i Isomerase 1,3-Bisphospho- glycerate 7 3-Phospho- glycerate 5 6 Aldolase Dihydroxyacetone phosphate (DHAP) 4 Figure 7.9ba-3 A closer look at glycolysis (part 2a, step 3) 21

Glycolysis: Energy Payoff Phase Figure 7.9bb-3 Glycolysis: Energy Payoff Phase 2 ATP 2 H2O 2 ADP 2 2 2 2 Phospho- glyceromutase Enolase Pyruvate kinase 9 3-Phospho- glycerate 8 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) 10 Pyruvate Figure 7.9bb-3 A closer look at glycolysis (part 2b, step 3) 22

ENERGY-REQUIRING STEPS fructose–1,6–bisphosphate Glycolysis ENERGY-REQUIRING STEPS OF GLYCOLYSIS glucose ATP 2 ATP invested ADP P glucose–6–phosphate P fructose–6–phosphate ATP ADP P P fructose–1,6–bisphosphate DHAP Fig. 8-4b, p.127

ENERGY-RELEASING STEPS 1,3–bisphosphoglycerate 1,3–bisphosphoglycerate Glycolysis ENERGY-RELEASING STEPS OF GLYCOLYSIS P P PGAL PGAL NAD+ NAD+ NADH NADH Pi Pi P P P P 1,3–bisphosphoglycerate 1,3–bisphosphoglycerate substrate-level phsphorylation ADP ADP ATP ATP 2 ATP PRODUCED P P 3–phosphoglycerate 3–phosphoglycerate Fig. 8-4c, p.127

Glycolysis P P 2–phosphoglycerate 2–phosphoglycerate H2O H2O P P PEP substrate-level phsphorylation ADP ADP ATP ATP 2 ATP produced pyruvate pyruvate Fig. 8-4d, p.127

Energy-Requiring Steps 2 ATP invested Energy-Requiring Steps of Glycolysis glucose ADP P ATP glucose-6-phosphate fructose-6-phosphate P ATP fructose1,6-bisphosphate P ADP PGAL P Figure 8-4(2) Page 127

1,3-bisphosphoglycerate 1,3-bisphosphoglycerate PGAL PGAL NAD+ NAD+ Pi NADH Pi NADH P P P P 1,3-bisphosphoglycerate 1,3-bisphosphoglycerate ADP ADP ATP ATP P P 3-phosphoglycerate 3-phosphoglycerate P P 2-phosphoglycerate 2-phosphoglycerate H2O H2O P P PEP PEP ADP ADP ATP ATP pyruvate pyruvate Figure 8-4 Page 127

Concept 7.3: After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules _________________________________________________ ________________________________________________________________________________________________________________ _________________________________________________________________ © 2014 Pearson Education, Inc. 28

Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Figure 7.UN07 Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Glycolysis Figure 7.UN07 In-text figure, mini-map, pyruvate oxidation, p. 142 ATP ATP ATP 29

Overview of Aerobic Respiration CYTOPLASM glucose ATP 2 ATP 4 Glycolysis e- + H+ (2 ATP net) 2 NADH 2 pyruvate e- + H+ 2 CO2 Overview of Aerobic Respiration 2 NADH e- + H+ 8 NADH 4 CO2 KrebsCycle e- + H+ 2 ATP 2 FADH2 e- Electron Transfer Phosphorylation 32 ATP H+ water e- + oxygen Typical Energy Yield: 36 ATP Fig. 8-3, p. 135

Citric acid cycle Figure 7.10 Pyruvate (from glycolysis, 2 molecules per glucose) CYTOSOL CO2 NAD CoA NADH  H Acetyl CoA MITOCHONDRION CoA CoA Citric acid cycle Figure 7.10 An overview of pyruvate oxidation and the citric acid cycle 2 CO2 FADH2 3 NAD FAD 3 NADH  3 H ADP  P i ATP 31

2 molecules per glucose) CYTOSOL Figure 7.10a Pyruvate (from glycolysis, 2 molecules per glucose) CYTOSOL CO2 NAD CoA Figure 7.10a An overview of pyruvate oxidation and the citric acid cycle (part 1: pyruvate oxidation) NADH  H Acetyl CoA MITOCHONDRION CoA 32

Citric acid cycle Acetyl CoA CoA CoA 2 CO2 FADH2 3 NAD 3 NADH FAD Figure 7.10b Acetyl CoA CoA CoA Citric acid cycle 2 CO2 FADH2 3 NAD Figure 7.10b An overview of pyruvate oxidation and the citric acid cycle (part 2: citric acid cycle) 3 NADH FAD  3 H ADP  P i ATP 33

Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Figure 7.UN08 Citric acid cycle Oxidative phosphorylation Pyruvate oxidation Glycolysis Figure 7.UN08 In-text figure, mini-map, citric acid cycle, p. 143 ATP ATP ATP 34

Citric acid cycle Figure 7.11-6 Acetyl CoA 1 Oxaloacetate 8 2 Malate CoA-SH NADH 1  H H2O NAD Oxaloacetate 8 2 Malate Citrate Isocitrate NAD Citric acid cycle 3 NADH 7  H H2O CO2 Fumarate CoA-SH -Ketoglutarate Figure 7.11-6 A closer look at the citric acid cycle (step 8) 6 4 CoA-SH 5 FADH2 CO2 NAD FAD Succinate P NADH i GTP GDP Succinyl CoA  H ADP ATP formation ATP 35

Start: Acetyl CoA adds its two-carbon group to oxaloacetate, producing Figure 7.11a Start: Acetyl CoA adds its two-carbon group to oxaloacetate, producing citrate; this is a highly exergonic reaction. Acetyl CoA CoA-SH 1 H2O Oxaloacetate Figure 7.11a A closer look at the citric acid cycle (part 1) 2 Citrate Isocitrate 36

Isocitrate is oxidized; NAD is reduced. Figure 7.11b Isocitrate Redox reaction: Isocitrate is oxidized; NAD is reduced. NAD NADH 3  H CO2 CO2 release CoA-SH -Ketoglutarate 4 Figure 7.11b A closer look at the citric acid cycle (part 2) CO2 release CO2 NAD Redox reaction: After CO2 release, the resulting four-carbon molecule is oxidized (reducing NAD), then made reactive by addition of CoA. NADH Succinyl CoA  H 37

Succinate is oxidized; FAD is reduced. Figure 7.11c Fumarate 6 CoA-SH 5 FADH2 FAD Redox reaction: Succinate is oxidized; FAD is reduced. Succinate P i GTP GDP Succinyl CoA Figure 7.11c A closer look at the citric acid cycle (part 3) ADP ATP formation ATP 38

Redox reaction: Malate is oxidized; NAD is reduced. Oxaloacetate 8 Figure 7.11d Redox reaction: Malate is oxidized; NAD is reduced. NADH  H NAD 8 Oxaloacetate Malate 7 Figure 7.11d A closer look at the citric acid cycle (part 4) H2O Fumarate 39

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The Pathway of Electron Transport _________________________________________________________________________ _______________________________________________________________________ ________________________________________________________________________ © 2014 Pearson Education, Inc. 42

Oxidative phosphorylation: electron transport and chemiosmosis Citric Figure 7.UN09 Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle Pyruvate oxidation Glycolysis Figure 7.UN09 In-text figure, mini-map, oxidative phosphorylation, p. 144 ATP ATP ATP 43

Free energy (G) relative to O2 (kcal/mol) Figure 7.12 NADH 50 2 e− NAD FADH2 Multiprotein complexes 2 e− FAD 40 I FMN II Fe•S Fe•S Q III Cyt b 30 Fe•S Cyt c1 IV Free energy (G) relative to O2 (kcal/mol) Cyt c Cyt a Cyt a3 20 Figure 7.12 Free-energy change during electron transport 10 2 e− (originally from NADH or FADH2) 2 H  ½ O2 H2O 44

Free energy (G) relative to O2 (kcal/mol) Figure 7.12a NADH 50 2 e− NAD FADH2 2 e− FAD Multiprotein complexes I 40 FMN II Fe•S Fe•S Q III Cyt b Free energy (G) relative to O2 (kcal/mol) Fe•S 30 Cyt c1 IV Cyt c Figure 7.12a Free-energy change during electron transport (part 1) Cyt a Cyt a3 20 2 e− 10 45

Free energy (G) relative to O2 (kcal/mol) Figure 7.12b 30 Cyt c1 IV Cyt c Cyt a Cyt a3 20 Free energy (G) relative to O2 (kcal/mol) 2 e− 10 (originally from NADH or FADH2) Figure 7.12b Free-energy change during electron transport (part 2) 2 H  ½ O2 H2O 46

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Chemiosmosis: The Energy-Coupling Mechanism _________________________________________________________________________________ ______________________________________________, emphasizing capacity to do work ________________________________________________ _______________________________________ _________________________________________________________________________ © 2014 Pearson Education, Inc. 48

H INTERMEMBRANE SPACE Stator Rotor Internal rod Catalytic knob ADP  Figure 7.13 H INTERMEMBRANE SPACE Stator Rotor Internal rod Catalytic knob Figure 7.13 ATP synthase, a molecular mill ADP  P ATP MITOCHONDRIAL MATRIX i 49

Oxidative phosphorylation: electron transport and chemiosmosis Citric Figure 7.UN09 Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle Pyruvate oxidation Glycolysis Figure 7.UN09 In-text figure, mini-map, oxidative phosphorylation, p. 146 ATP ATP ATP 50

Electron transport chain Oxidative phosphorylation Figure 7.14 H H Protein complex of electron carriers H H Cyt c IV Q III I ATP synthase II 2 H  ½ O2 H2O FADH2 FAD NADH NAD Figure 7.14 Chemiosmosis couples the electron transport chain to ATP synthesis ADP  P ATP i (carrying electrons from food) H 1 Electron transport chain 2 Chemiosmosis Oxidative phosphorylation 51

Electron transport chain Figure 7.14a H H Protein complex of electron carriers H Cyt c IV Q III I II 2 H  ½ O2 H2O FADH2 FAD Figure 7.14a Chemiosmosis couples the electron transport chain to ATP synthesis (part 1: electron transport chain) NAD NADH (carrying electrons from food) 1 Electron transport chain 52

2 ATP synthase Chemiosmosis H H ADP  ATP i P Figure 7.14b Figure 7.14b Chemiosmosis couples the electron transport chain to ATP synthesis (part 2: chemiosmosis) ADP  P ATP i H 2 Chemiosmosis 53

Video: ATP Synthase 3-D Side View Video: ATP Synthase 3-D Top View © 2014 Pearson Education, Inc. 54

An Accounting of ATP Production by Cellular Respiration ____________________________: ________________________________________ _____________________________________________________ There are several reasons why the number of ATP molecules is not known exactly © 2014 Pearson Education, Inc. 55

Electron shuttles span membrane MITOCHONDRION 2 NADH CYTOSOL or Figure 7.15 Electron shuttles span membrane MITOCHONDRION 2 NADH CYTOSOL or 2 FADH2 2 NADH 2 NADH 6 NADH 2 FADH2 Glycolysis Pyruvate oxidation 2 Acetyl CoA Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle 2 Pyruvate Glucose  2 ATP Figure 7.15 ATP yield per molecule of glucose at each stage of cellular respiration  2 ATP  about 26 or 28 ATP About 30 or 32 ATP Maximum per glucose: 56

Electron shuttles span membrane 2 NADH or 2 FADH2 2 NADH Glycolysis 2 Figure 7.15a Electron shuttles span membrane 2 NADH or 2 FADH2 2 NADH Glycolysis 2 Pyruvate Glucose Figure 7.15a ATP yield per molecule of glucose at each stage of cellular respiration (part 1: glycolysis)  2 ATP 57

Pyruvate oxidation 2 Acetyl CoA Citric acid cycle Figure 7.15b 2 NADH 6 NADH 2 FADH2 Pyruvate oxidation 2 Acetyl CoA Citric acid cycle Figure 7.15b ATP yield per molecule of glucose at each stage of cellular respiration (part 2: citric acid cycle)  2 ATP 58

2 NADH or 2 FADH2 2 NADH 6 NADH 2 FADH2 Oxidative phosphorylation: Figure 7.15c 2 NADH or 2 FADH2 2 NADH 6 NADH 2 FADH2 Oxidative phosphorylation: electron transport and chemiosmosis Figure 7.15c ATP yield per molecule of glucose at each stage of cellular respiration (part 3: oxidative phosphorylation)  about 26 or 28 ATP 59

About Maximum per glucose: 30 or 32 ATP Figure 7.15d Figure 7.15d ATP yield per molecule of glucose at each stage of cellular respiration (part 4: yield per glucose) 60

Concept 7.5: Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen ____________________________________ _______________________________________________________________________ © 2014 Pearson Education, Inc. 61

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Types of Fermentation ______________________________________________________, (can be reused by glycolysis) ______________________________________________________ © 2014 Pearson Education, Inc. 63

_______________________________________ ___________________________________________________ ________________________________________________________ Animation: Fermentation Overview © 2014 Pearson Education, Inc. 64

(a) Alcohol fermentation (b) Lactic acid fermentation Figure 7.16 2 ADP  2 P 2 ADP  2 i 2 ATP P i 2 ATP Glucose Glycolysis Glucose Glycolysis 2 Pyruvate 2 NAD 2 NADH 2 CO2 2 NAD 2 NADH  2 H  2 H 2 Pyruvate Figure 7.16 Fermentation 2 Ethanol 2 Acetaldehyde 2 Lactate (a) Alcohol fermentation (b) Lactic acid fermentation 65

(a) Alcohol fermentation Figure 7.16a 2 ADP  2 P 2 ATP i Glucose Glycolysis 2 Pyruvate 2 NAD 2 NADH 2 CO2  2 H Figure 7.16a Fermentation (part 1: alcohol) 2 Acetaldehyde 2 Ethanol (a) Alcohol fermentation 66

(b) Lactic acid fermentation Figure 7.16b 2 ADP  2 P 2 ATP i Glucose Glycolysis 2 NAD 2 NADH  2 H 2 Pyruvate Figure 7.16b Fermentation (part 2: lactic acid) 2 Lactate (b) Lactic acid fermentation 67

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Comparing Fermentation with Anaerobic and Aerobic Respiration ________________________ __________ __________________________ ____________________________________________________________________ © 2014 Pearson Education, Inc. 69

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Ethanol, lactate, or other products Citric acid cycle Figure 7.17 Glucose Glycolysis CYTOSOL Pyruvate No O2 present: Fermentation O2 present: Aerobic cellular respiration MITOCHONDRION Ethanol, lactate, or other products Acetyl CoA Figure 7.17 Pyruvate as a key juncture in catabolism Citric acid cycle 71

The Evolutionary Significance of Glycolysis _____________________________________________________________ _____________________________________________________________________ © 2014 Pearson Education, Inc. 72

The Versatility of Catabolism _________________________________________ _______________________________________________________________________________ © 2014 Pearson Education, Inc. 73

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Amino acids Fatty acids Citric acid cycle Oxidative phosphorylation Figure 7.18-5 Proteins Carbohydrates Fats Amino acids Sugars Glycerol Fatty acids Glycolysis Glucose Glyceraldehyde 3- P NH3 Pyruvate Figure 7.18-5 The catabolism of various molecules from food (step 5) Acetyl CoA Citric acid cycle Oxidative phosphorylation 75

Figure 7.UN10b Figure 7.UN10b Skills exercise: making a bar graph and interpreting the data (part 2) 76

Inputs Glycolysis Glucose ATP  2 NADH Figure 7.UN11 Inputs Outputs Glycolysis Glucose 2 Pyruvate  2 ATP  2 NADH Figure 7.UN11 Summary of key concepts: pyruvate 77

CO2 Inputs Outputs 2 Pyruvate 2 Acetyl CoA 2 ATP 8 NADH Citric acid Figure 7.UN12 Inputs Outputs 2 Pyruvate 2 Acetyl CoA 2 ATP 8 NADH Citric acid cycle 2 Oxaloacetate CO2 6 2 FADH2 Figure 7.UN12 Summary of key concepts: citric acid cycle 78

(carrying electrons from food) Figure 7.UN13a INTERMEMBRANE SPACE H H Protein complex of electron carriers H Cyt c IV Q III I Figure 7.UN13a Summary of key concepts: oxidative phosphorylation (part 1) II 2 H  ½O2 H2O FADH2 FAD NADH NAD MITOCHONDRIAL MATRIX (carrying electrons from food) 79

INTER- MEMBRANE SPACE H MITO- ATP CHONDRIAL synthase MATRIX ADP  ATP Figure 7.UN13b INTER- MEMBRANE SPACE H MITO- CHONDRIAL MATRIX ATP synthase Figure 7.UN13b Summary of key concepts: oxidative phosphorylation (part 2) ADP  P H ATP i 80

Overview of Aerobic Respiration CYTOPLASM glucose ATP 2 ATP 4 Glycolysis e- + H+ (2 ATP net) 2 NADH 2 pyruvate e- + H+ 2 CO2 Overview of Aerobic Respiration 2 NADH e- + H+ 8 NADH 4 CO2 KrebsCycle e- + H+ 2 ATP 2 FADH2 e- Electron Transfer Phosphorylation 32 ATP H+ water e- + oxygen Typical Energy Yield: 36 ATP Fig. 8-3, p. 135