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Chapter 9 Cellular Respiration: Harvesting Chemical Energy

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1 Chapter 9 Cellular Respiration: Harvesting Chemical Energy

2 Overview: Life Is Work Living cells require energy from outside sources Some animals, such as the giant panda, obtain energy by eating plants, and some animals feed on other organisms that eat plants For the Discovery Video Space Plants, go to Animation and Video Files. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

3 Energy flows into an ecosystem as sunlight and leaves as heat
Photosynthesis generates O2 and organic molecules, which are used in cellular respiration Cells use chemical energy stored in organic molecules to regenerate ATP, which powers work Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

4 Organic molecules Cellular respiration in mitochondria
Fig. 9-2 Light energy ECOSYSTEM Photosynthesis in chloroplasts Organic molecules CO2 + H2O + O2 Cellular respiration in mitochondria Figure 9.2 Energy flow and chemical recycling in ecosystems ATP ATP powers most cellular work Heat energy

5 Concept 9.1: Catabolic pathways yield energy by oxidizing organic fuels
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

6 Catabolic Pathways and Production of ATP
Catabolic Pathways: The breakdown of organic molecules (exergonic) 2 types: Fermentation is a partial degradation of sugars that occurs without O2 (anaerobic) Aerobic respiration consumes organic molecules and O2 and yields ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

7 Cellular respiration includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the sugar glucose: C6H12O6 + 6 O2  6 CO2 + 6 H2O + Energy (ATP + heat) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

8 Redox Reactions: Oxidation and Reduction
The transfer of electrons during chemical reactions releases energy stored in organic molecules This released energy is ultimately used to synthesize ATP from ADP + Pi which is regenerated by burning fuels during respiration Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

9 The Principle of Redox Chemical reactions that transfer electrons between reactants are called oxidation- reduction reactions, or redox reactions In oxidation, a substance loses electrons, or is oxidized (loses energy) In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced), gains energy Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

10 becomes oxidized (loses electron) becomes reduced (gains electron)
Fig. 9-UN1 becomes oxidized (loses electron) becomes reduced (gains electron)

11 becomes oxidized becomes reduced
Fig. 9-UN2 becomes oxidized becomes reduced

12 Methane (reducing agent) Oxygen (oxidizing agent)
Fig. 9-3 Reactants Products becomes oxidized becomes reduced Figure 9.3 Methane combustion as an energy-yielding redox reaction Methane (reducing agent) Oxygen (oxidizing agent) Carbon dioxide Water The electron donor is called the reducing agent The electron receptor is called the oxidizing agent

13 Oxidation of Organic Fuel Molecules During Cellular Respiration
During cellular respiration, the fuel (such as glucose) is oxidized, and O2 is reduced: becomes oxidized becomes reduced Dehydrogenase Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

14 Stepwise Energy Harvest via NAD+ and the Electron Transport Chain
In cellular respiration, glucose and other organic molecules are broken down in a series of steps Electrons from organic compounds are usually first transferred to NAD+, a coenzyme As an electron acceptor, NAD+ functions as an oxidizing agent during cellular respiration Each NADH (the reduced form of NAD+) represents stored energy that is tapped to synthesize ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

15 NADH H+ NAD+ + 2[H] + H+ 2 e– + 2 H+ 2 e– + H+ Dehydrogenase
Fig. 9-4 2 e– + 2 H+ 2 e– + H+ NADH H+ Dehydrogenase Reduction of NAD+ NAD+ + 2[H] + H+ Oxidation of NADH Nicotinamide (reduced form) Nicotinamide (oxidized form) Figure 9.4 NAD+ as an electron shuttle Figure 9.4 NAD+ as an electron shuttle

16 NADH passes the electrons to the electron transport chain
Unlike an uncontrolled reaction, the electron transport chain passes electrons in a series of steps instead of one explosive reaction O2 pulls electrons down the chain in an energy-yielding tumble The energy yielded is used to regenerate ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

17 (a) Uncontrolled reaction (b) Cellular respiration
Fig. 9-5 H2 + 1/2 O2 2 H + 1/2 O2 (from food via NADH) Controlled release of energy for synthesis of ATP 2 H e– ATP Explosive release of heat and light energy ATP Electron transport chain Free energy, G Free energy, G ATP 2 e– Figure 9.5 An introduction to electron transport chains 1/2 O2 2 H+ H2O H2O (a) Uncontrolled reaction (b) Cellular respiration

18 The Stages of Cellular Respiration: A Preview
Cellular respiration has three stages: Glycolysis (breaks down glucose into two molecules of pyruvate), cytosol The citric acid cycle (completes the breakdown of glucose), mitochondria Oxidative phosphorylation (accounts for most of the ATP synthesis), inner mitochondrial membrane Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

19 Electrons carried via NADH ATP Substrate-level phosphorylation
Fig Electrons carried via NADH Glycolysis Glucose Pyruvate Cytosol Figure 9.6 An overview of cellular respiration ATP Substrate-level phosphorylation

20 Electrons carried via NADH Electrons carried via NADH and FADH2
Fig Electrons carried via NADH Electrons carried via NADH and FADH2 Glycolysis Citric acid cycle Glucose Pyruvate Mitochondrion Cytosol Figure 9.6 An overview of cellular respiration ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation

21 Electrons carried via NADH Electrons carried via NADH and FADH2
Fig Electrons carried via NADH Electrons carried via NADH and FADH2 Oxidative phosphorylation: electron transport and chemiosmosis Glycolysis Citric acid cycle Glucose Pyruvate Mitochondrion Cytosol Figure 9.6 An overview of cellular respiration ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation

22 Oxidative phosphorylation accounts for almost 90% of the ATP generated by cellular respiration (powered by redox reactions) A smaller amount of ATP is formed in glycolysis and the citric acid cycle by substrate-level phosphorylation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

23 Enzyme Enzyme ADP P Substrate + ATP Product
Fig. 9-7 Enzyme Enzyme ADP P Substrate + ATP Figure 9.7 Substrate-level phosphorylation Product Figure 9.7 Substrate-level phosphorylation

24 Glycolysis occurs in the cytoplasm and has two major phases:
Concept 9.2: Glycolysis harvests chemical energy by oxidizing 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/consuming phase Energy producing/payoff phase Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

25 Energy investment phase
Fig. 9-8 Energy investment phase Glucose 2 ADP + 2 P 2 ATP used Energy payoff phase 4 ADP + 4 P 4 ATP formed 2 NAD e– + 4 H+ 2 NADH + 2 H+ Figure 9.8 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 e– + 4 H+ 2 NADH + 2 H+

26 Glucose ATP 1 Hexokinase ADP Glucose-6-phosphate Fig. 9-9-1
Figure 9.9 A closer look at glycolysis Glucose-6-phosphate

27 Glucose-6-phosphate 2 Phosphogluco- isomerase Fructose-6-phosphate
Fig Glucose ATP 1 Hexokinase ADP Glucose-6-phosphate Glucose-6-phosphate 2 Phosphoglucoisomerase 2 Phosphogluco- isomerase Fructose-6-phosphate Figure 9.9 A closer look at glycolysis Fructose-6-phosphate

28 Fructose- 1, 6-bisphosphate
Fig Glucose ATP 1 1 Hexokinase ADP Fructose-6-phosphate Glucose-6-phosphate 2 2 Phosphoglucoisomerase ATP 3 Phosphofructo- kinase Fructose-6-phosphate ATP 3 3 ADP Phosphofructokinase ADP Figure 9.9 A closer look at glycolysis Fructose- 1, 6-bisphosphate Fructose- 1, 6-bisphosphate

29 Aldolase Isomerase Fructose- 1, 6-bisphosphate 4 5 Dihydroxyacetone
Fig Glucose ATP 1 Hexokinase ADP Glucose-6-phosphate 2 Phosphoglucoisomerase Fructose- 1, 6-bisphosphate 4 Fructose-6-phosphate Aldolase ATP 3 Phosphofructokinase ADP Figure 9.9 A closer look at glycolysis 5 Isomerase Fructose- 1, 6-bisphosphate 4 Aldolase 5 Isomerase Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate

30 Glyceraldehyde- 3-phosphate
Fig 2 NAD+ 6 Triose phosphate dehydrogenase 2 NADH 2 P i + 2 H+ 2 2 1, 3-Bisphosphoglycerate Glyceraldehyde- 3-phosphate 2 NAD+ 6 Triose phosphate dehydrogenase 2 P 2 NADH i + 2 H+ Figure 9.9 A closer look at glycolysis 2 1, 3-Bisphosphoglycerate

31 2 2 ADP 2 ATP 2 3-Phosphoglycerate 1, 3-Bisphosphoglycerate 7
Fig 2 NAD+ 6 Triose phosphate dehydrogenase 2 NADH 2 P i + 2 H+ 2 1, 3-Bisphosphoglycerate 2 ADP 7 Phosphoglycerokinase 2 ATP 2 1, 3-Bisphosphoglycerate 2 ADP 2 3-Phosphoglycerate 7 Phosphoglycero- kinase 2 ATP Figure 9.9 A closer look at glycolysis 2 3-Phosphoglycerate

32 2 3-Phosphoglycerate 8 Phosphoglycero- mutase 2 2-Phosphoglycerate
Fig 2 NAD+ 6 Triose phosphate dehydrogenase 2 NADH 2 P i + 2 H+ 2 1, 3-Bisphosphoglycerate 2 ADP 7 Phosphoglycerokinase 2 ATP 2 3-Phosphoglycerate 2 3-Phosphoglycerate 8 Phosphoglyceromutase 8 Phosphoglycero- mutase 2 2-Phosphoglycerate Figure 9.9 A closer look at glycolysis 2 2-Phosphoglycerate

33 2 2-Phosphoglycerate Enolase 2 H2O 2 Phosphoenolpyruvate 9 Fig. 9-9-8
2 NAD+ 6 Triose phosphate dehydrogenase 2 NADH 2 P i + 2 H+ 2 1, 3-Bisphosphoglycerate 2 ADP 7 Phosphoglycerokinase 2 ATP 2 2-Phosphoglycerate 2 3-Phosphoglycerate 8 Phosphoglyceromutase 9 Enolase 2 H2O 2 2-Phosphoglycerate 9 Enolase Figure 9.9 A closer look at glycolysis 2 H2O 2 Phosphoenolpyruvate 2 Phosphoenolpyruvate

34 2 Phosphoenolpyruvate 2 ADP 10 Pyruvate kinase 2 ATP 2 Pyruvate
Fig 2 NAD+ 6 Triose phosphate dehydrogenase 2 NADH 2 P i + 2 H+ 2 1, 3-Bisphosphoglycerate 2 ADP 7 Phosphoglycerokinase 2 ATP 2 Phosphoenolpyruvate 2 ADP 2 3-Phosphoglycerate 8 10 Phosphoglyceromutase Pyruvate kinase 2 ATP 2 2-Phosphoglycerate 9 Enolase 2 H2O Figure 9.9 A closer look at glycolysis 2 Phosphoenolpyruvate 2 ADP 10 Pyruvate kinase 2 ATP 2 Pyruvate 2 Pyruvate

35 In the presence of O2, pyruvate enters the mitochondrion
Concept 9.3: The citric acid cycle completes the energy-yielding oxidation of organic molecules In the presence of O2, pyruvate enters the mitochondrion Before the citric acid cycle can begin, pyruvate must be converted to acetyl CoA, which links the cycle to glycolysis Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

36 CYTOSOL MITOCHONDRION NAD+ NADH + H+ 2 1 3 Acetyl CoA Pyruvate
Fig. 9-10 CYTOSOL MITOCHONDRION NAD+ NADH + H+ 2 1 3 Acetyl CoA Figure 9.10 Conversion of pyruvate to acetyl CoA, the junction between glycolysis and the citric acid cycle Pyruvate Coenzyme A CO2 Transport protein Figure 9.10 Conversion of pyruvate to acetyl CoA, the junction between glycolysis and the citric acid cycle

37 Fig. 9-11 Pyruvate CO2 NAD+ CoA The citric acid cycle, also called the Krebs cycle, takes place within the mitochondrial matrix The cycle oxidizes organic fuel derived from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn NADH + H+ Acetyl CoA CoA CoA Citric acid cycle 2 CO2 Figure 9.11 An overview of the citric acid cycle FADH2 3 NAD+ FAD 3 NADH + 3 H+ ADP + P i ATP

38

39 The citric acid cycle has eight steps, each catalyzed by a specific enzyme
The acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate The next seven steps decompose the citrate back to oxaloacetate, making the process a cycle The NADH and FADH2 produced by the cycle relay electrons extracted from food to the electron transport chain Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

40 Citric acid cycle Succinyl CoA
Fig Acetyl CoA CoA—SH NADH +H+ 1 H2O NAD+ 8 Oxaloacetate 2 Malate Citrate Isocitrate NAD+ Citric acid cycle NADH 3 7 + H+ H2O CO2 Fumarate CoA—SH -Keto- glutarate Figure 9.12 A closer look at the citric acid cycle 4 6 CoA—SH FADH2 5 CO2 NAD+ FAD Succinate P NADH i GTP GDP Succinyl CoA + H+ ADP ATP

41 Concept 9.4: During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis Following glycolysis and the citric acid cycle, NADH and FADH2 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 For the Cell Biology Video ATP Synthase 3D Structure — Side View, go to Animation and Video Files. For the Cell Biology Video ATP Synthase 3D Structure — Top View, go to Animation and Video Files. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

42 The Pathway of Electron Transport
The electron transport chain is in the cristae of the mitochondrion Most of the chain’s components are proteins The carriers alternate reduced and oxidized states as they accept and donate electrons Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

43 Figure 9.13 Free-energy change during electron transport
NADH 50 2 e– NAD+ FADH2 2 e– FAD Multiprotein complexes 40 FMN FAD Fe•S  Fe•S Q  Cyt b Fe•S 30 Cyt c1 IV Free energy (G) relative to O2 (kcal/mol) Cyt c Cyt a Cyt a3 20 Figure 9.13 Free-energy change during electron transport e– 10 2 (from NADH or FADH2) 2 H+ + 1/2 O2 H2O

44 The electron transport chain generates no ATP
Electrons are transferred from NADH or FADH2 to the electron transport chain Electrons are passed through a number of proteins including cytochromes (each with an iron atom) to O2 The electron transport chain generates no ATP The chain’s function is to break the large free-energy drop from food to O2 into smaller steps that release energy in manageable amounts Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

45

46 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 H+ then moves back across the membrane, passing through channels in 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 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

47 INTERMEMBRANE SPACE H+ Stator Rotor Internal rod Cata- lytic knob ADP
Fig. 9-14 INTERMEMBRANE SPACE H+ Stator Rotor Internal rod Figure 9.14 ATP synthase, a molecular mill Cata- lytic knob ADP + P ATP i MITOCHONDRIAL MATRIX

48 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 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

49 Electron transport chain 2 Chemiosmosis
Fig. 9-16 H+ H+ H+ H+ Protein complex of electron carriers Cyt c V Q  ATP synthase  2 H+ + 1/2O2 H2O FADH2 FAD NADH NAD+ Figure 9.16 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

50 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 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

51 Fig. 9-17 CYTOSOL Electron shuttles span membrane MITOCHONDRION 2 NADH or 2 FADH2 2 NADH 2 NADH 6 NADH 2 FADH2 Glycolysis Oxidative phosphorylation: electron transport and chemiosmosis 2 Pyruvate 2 Acetyl CoA Citric acid cycle Glucose + 2 ATP + 2 ATP + about 32 or 34 ATP Figure 9.17 ATP yield per molecule of glucose at each stage of cellular respiration About 36 or 38 ATP Maximum per glucose:

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53 Most cellular respiration requires O2 to produce ATP
Concept 9.5: Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen Most cellular respiration requires O2 to produce ATP Glycolysis can produce ATP with or without O2 (in aerobic or anaerobic conditions) In the absence of O2, glycolysis couples with fermentation or anaerobic respiration to produce ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

54 Anaerobic respiration uses an electron transport chain with an electron acceptor other than O2, for example sulfate Fermentation uses phosphorylation instead of an electron transport chain to generate ATP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

55 Types of Fermentation Fermentation consists of glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysis Two common types are alcohol fermentation and lactic acid fermentation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

56 (a) Alcohol fermentation
Fig. 9-18a In alcohol fermentation, pyruvate is converted to ethanol in two steps, with the first releasing CO2 Alcohol fermentation by yeast is used in brewing, winemaking, and baking 2 ADP + 2 P 2 ATP i Glucose Glycolysis 2 Pyruvate 2 NAD+ 2 NADH 2 CO2 + 2 H+ Figure 9.18a Fermentation 2 Acetaldehyde 2 Ethanol (a) Alcohol fermentation

57 In lactic acid fermentation, pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2 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 O2 is scarce Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

58 (b) Lactic acid fermentation
Fig. 9-18b 2 ADP + 2 P 2 ATP i Glucose Glycolysis 2 NAD+ 2 NADH + 2 H+ 2 Pyruvate Figure 9.18b Fermentation In lactic acid fermentation, pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2 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 O2 is scarce 2 Lactate (b) Lactic acid fermentation

59 Fermentation and Aerobic Respiration Compared
Both processes use glycolysis to oxidize glucose and other organic fuels to pyruvate final electron acceptors: Fermentation: an organic molecule (such as pyruvate or acetaldehyde) Aerobic respiration: O2 ATP production: Cellular respiration produces 38 ATP per glucose molecule fermentation produces 2 ATP per glucose molecule Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

60 Obligate anaerobes carry out fermentation or anaerobic respiration and cannot survive in the presence of O2 Yeast and many bacteria are facultative anaerobes, meaning that they can survive using either fermentation or cellular respiration Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

61 Ethanol or lactate Citric acid cycle
Fig. 9-19 Glucose Glycolysis CYTOSOL Pyruvate O2 present: Aerobic cellular respiration No O2 present: Fermentation MITOCHONDRION Ethanol or lactate Acetyl CoA Figure 9.19 Pyruvate as a key juncture in catabolism Citric acid cycle

62 The Evolutionary Significance of Glycolysis
Glycolysis occurs in nearly all organisms Glycolysis probably evolved in ancient prokaryotes before there was oxygen in the atmosphere Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

63 Concept 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 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

64 The Versatility of Catabolism
Catabolic pathways funnel electrons from many kinds of organic molecules into cellular respiration Glycolysis accepts a wide range of carbohydrates Proteins must be digested to amino acids; amino groups can feed glycolysis or the citric acid cycle Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

65 Fatty acids are broken down by beta oxidation and yield acetyl CoA
Fats are digested to glycerol (used in glycolysis) and fatty acids (used in generating acetyl CoA) Fatty acids are broken down by beta oxidation and yield acetyl CoA An oxidized gram of fat produces more than twice as much ATP as an oxidized gram of carbohydrate Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

66 Citric acid cycle Oxidative phosphorylation
Fig. 9-20 Proteins Carbohydrates Fats Amino acids Sugars Glycerol Fatty acids Glycolysis Glucose Glyceraldehyde-3- P NH3 Pyruvate Acetyl CoA Figure 9.20 The catabolism of various molecules from food Citric acid cycle Oxidative phosphorylation

67 Biosynthesis (Anabolic Pathways)
The body uses small molecules to build other substances These small molecules may come directly from food, from glycolysis, or from the citric acid cycle Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings


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