Light energy ECOSYSTEM CO + H O Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O powers most cellular work Heat energy 1
becomes oxidized (loses electron) becomes reduced (gains electron)
becomes oxidized becomes reduced 3
Reactants Products becomes oxidized becomes reduced Methane (reducing agent) Oxygen (oxidizing agent) Carbon dioxide Water 4
becomes oxidized becomes reduced 5
Dehydrogenase 6
e + H + Dehydrogenase e + H + NADH H + NAD + + [H] Reduction of NAD + Oxidation of NADH + H + Nicotinamide (reduced form) Nicotinamide (oxidized form) 7
H + 1 / O H + 1 / O (from food via NADH) H + + e Controlled release of energy for synthesis of Free energy, G Explosive release of heat and light energy Free energy, G Electron transport chain e H + 1 / O H O H O (a) Uncontrolled reaction (b) Cellular respiration 8
Electrons carried via NADH Electrons carried via NADH and FADH Glycolysis Glucose Pyruvate Cytosol Mitochondrion Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation 9
Enzyme Enzyme ADP P Substrate + Product 10
Energy investment phase Glucose ADP + P used Energy payoff phase 4 ADP + 4 P 4 formed NAD + + 4 e + 4 H + NADH + H + Pyruvate + H O Net Glucose Pyruvate + H O 4 formed used NAD + + 4 e + 4 H + NADH + H + 11
Glucose 1 Hexokinase ADP Glucose-6-phosphate Phosphoglucoisomerase Fructose-6-phosphate 3 Phosphofructokinase Fructose- 1, 6-bisphosphate 4 Aldolase ADP 5 Isomerase Fructose- 1, 6-bisphosphate 4 Aldolase 5 Isomerase Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate 1
NAD + NADH + H + 6 Triose phosphate dehydrogenase P i 1, 3-Bisphosphoglycerate ADP 7 Phosphoglycerokinase 3-Phosphoglycerate 8 Phosphoglyceromutase Phosphoenolpyruvate ADP 10 Pyruvate kinase -Phosphoglycerate 9 Enolase H O Phosphoenolpyruvate ADP 10 Pyruvate kinase Pyruvate Pyruvate 13
CYTOSOL MITOCHONDRION NAD + NADH + H + Pyruvate Transport protein 1 3 CO Coenzyme A Acetyl CoA 14
Pyruvate NAD + NADH + H + CO CoA Acetyl CoA CoA CoA Citric acid cycle CO FADH FAD 3 3 NAD + NADH + 3 H + ADP + P i 15
Acetyl CoA CoA SH NADH +H + 1 H O NAD + 8 Oxaloacetate H O 7 Malate Citric acid cycle Citrate Isocitrate NAD + 3 CO NADH + H + Fumarate 6 CoA SH CoA SH 4 α-ketoglutarate FADH FAD Succinate 5 GTP GDP P i Succinyl CoA NAD + NADH + H + CO ADP 16
NADH 50 e NAD + FADH Free energy (G) relative to O (kcal/mol) 40 30 0 FMN Fe S Ι e FAD FAD Fe S ΙΙ Q Cyt b Fe S ΙΙΙ Multiprotein complexes Cyt c 1 Cyt c Cyt a IV Cyt a 3 10 e (from NADH or FADH ) 0 H + + 1 / O H O 17
INTERMEMBRANE SPACE Rotor H + Stator Internal rod Catalytic knob ADP + P i MITOCHONDRIAL MATRIX 18
H + H + Protein complex of electron carriers H + Cyt c H + Ι ΙΙ Q FADH ΙΙΙ FAD ΙV H + + 1 / O H O synthase NADH (carrying electrons from food) NAD + ADP + P i H + 1 Electron transport chain Chemiosmosis Oxidative phosphorylation 19
CYTOSOL Electron shuttles span membrane NADH or MITOCHONDRION FADH NADH NADH 6 NADH FADH Glycolysis Glucose Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis + + + about 3 or 34 Maximum per glucose: About 36 or 38 0
ADP + P i Glucose Glycolysis Pyruvate NAD + NADH + H + CO Ethanol Acetaldehyde (a) Alcohol fermentation ADP + P i Glucose Glycolysis NAD + NADH + H + Pyruvate Lactate (b) Lactic acid fermentation 1
Glucose CYTOSOL Glycolysis Pyruvate No O present: Fermentation O present: Aerobic cellular respiration Ethanol or lactate Acetyl CoA MITOCHONDRION Citric acid cycle
Proteins Carbohydrates Fats Amino acids Sugars Glycerol Fatty acids Glycolysis Glucose Glyceraldehyde-3- P NH 3 Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation 3
Glucose Inhibits Glycolysis Fructose-6-phosphate Phosphofructokinase Fructose-1,6-bisphosphate AMP Stimulates + Inhibits Pyruvate Acetyl CoA Citrate Citric acid cycle Oxidative phosphorylation 4