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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 9 Cellular Respiration.

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Presentation on theme: "Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 9 Cellular Respiration."— Presentation transcript:

1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 9 Cellular Respiration

2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Transformations

3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolism Respiration Link The giant panda obtains energy for its cells by eating plants

4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings E Transformations, Thermodynamics, Ecosystems Energy flows into ecosystem as sunlight, and out as heat Light energy ECOSYSTEM CO 2 + H 2 O Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O 2 ATP powers most cellular work Heat energy Figure 9.2

5 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolism Respiration Link Catabolic pathways yield Energy by oxidizing organic fuels

6 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Oxidation, Reduction (No way to make this fun) Reducing agents lose electrons and are oxidized, and the oxidizing agents gains electrons and is reduced. The oxidizing agent removes electrons from another substance, and is thus itself reduced. Because it "accepts" electrons, the oxidizing agent is also called an electron acceptor. Oxygen is the quintessential oxidizer.

7 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Catabolic Pathways and Production of ATP Breakdown of organic molecules is exergonic Energy Released

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolism Respiration Link Cellular respiration – Most prevalent and efficient catabolic pathway – Consumes O 2 and organic molecules e.g. glucose – Yields ATP

9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolism Respiration Link Glucose is oxidized oxygen is reduced The Big Idea Why We Eat and Breathe

10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Stepwise Energy Harvest Glucose oxidized in a series of steps

11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Electrons from Glyceraldehyde-3-Phosphate Electrons from organic compounds – Usually first transferred to NAD +, a coenzyme NAD + H O O OO–O– O O O–O– O O O P P CH 2 HO OH H H HOOH HO H H N+N+ C NH 2 H N H N N Nicotinamide (oxidized form) NH 2 + 2[H] (from food) Dehydrogenase Reduction of NAD + Oxidation of NADH 2 e – + 2 H + 2 e – + H + NADH O H H N C + Nicotinamide (reduced form) N Figure 9.4

12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Electrons from NADH NADH (reduced form of NAD +) – Passes electrons to the e - transport chain

13 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Follow the Bouncing Electrons e - transport chain – Passes e - in a series of steps instead of explosive reaction – Uses E from the e - transfer to form ATP

14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Oxidative phosphorylation – Driven by e - transport chain – Generates ATP

15 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

16 The 3 Stages of Cellular Respiration Glycolysis Citric acid cycle (Krebs cycle) Oxidative phosphorylation (Electron Transport/ Chemiosmosis)

17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Step by Step Glycolsis GlucosePyruvate ATP Substrate-level phosphorylation Mitochondrion

18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Step by Step ATP Substrate-level phosphorylation Mitochondrion Glycolsis GlucosePyruvate ATP Substrate-level phosphorylation Citric acid cycle

19 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Step by Step Electrons carried via NADH Glycolsis GlucosePyruvate ATP Substrate-level phosphorylation Electrons carried via NADH and FADH 2 Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis ATP Substrate-level phosphorylation Oxidative phosphorylation Mitochondrion

20 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis Glycolysis harvests E by oxidizing glucose to pyruvate Glycolysis – Means splitting sugar – Glucose pyruvate – Occurs in cytoplasm

21 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis Glycolysis: Breaks down glucose into two molecules of pyruvate Citric acid (Krebs)cycle: Completes breakdown of glucose

22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis 2 major phases – E investment phase – E payoff phase Glycolysis Citric acid cycle Oxidative phosphorylation ATP 2 ATP 4 ATP used formed Glucose 2 ATP + 2 P 4 ADP + 4 P 2 NAD e H + 2 NADH + 2 H + 2 Pyruvate + 2 H 2 O Energy investment phase Energy payoff phase Glucose 2 Pyruvate + 2 H 2 O 4 ATP formed – 2 ATP used 2 ATP 2 NAD e – + 4 H + 2 NADH + 2 H + Figure 9.8

23 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Dihydroxyacetone phosphate Glyceraldehyde- 3-phosphate H H H H H OH HO CH 2 OH H H H H O H OH HO OH P CH 2 O P H O H HO H CH 2 OH P O CH 2 O O P HO H H OH O P CH 2 C O CH 2 OH H C CHOH CH 2 O O P ATP ADP Hexokinase Glucose Glucose-6-phosphate Fructose-6-phosphate ATP ADP Phosphoglucoisomerase Phosphofructokinase Fructose- 1, 6-bisphosphate Aldolase Isomerase Glycolysis CH 2 OH Oxidative phosphorylation Citric acid cycle Figure 9.9 A Glycolysis: Energy Investment

24 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2 NAD + NADH H + Triose phosphate dehydrogenase 2 P i 2 P C CHOH O P O CH 2 O 2 O–O– 1, 3-Bisphosphoglycerate 2 ADP 2 ATP Phosphoglycerokinase CH 2 OP 2 C CHOH 3-Phosphoglycerate Phosphoglyceromutase O–O– C C CH 2 OH H O P 2-Phosphoglycerate 2 H 2 O 2 O–O– Enolase C C O P O CH 2 Phosphoenolpyruvate 2 ADP 2 ATP Pyruvate kinase O–O– C C O O CH Pyruvate O Figure 9.8 B Glycolysis: Energy Pay Off

25 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Krebs Cycle Citric acid (or Krebs, or TCA) cycle completes the E-yielding oxidation of organic molecules Takes place in matrix of mitochondrion

26 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Krebs Cycle Pyruvate first converted to acetyl CoA, links cycle to glycolysis CYTOSOLMITOCHONDRION NADH + H + NAD CO 2 Coenzyme A Pyruvate Acetyle CoA S CoA C CH 3 O Transport protein O–O– O O C C CH 3

27 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Krebs Cycle Overview of citric acid cycle ATP 2 CO 2 3 NAD + 3 NADH + 3 H + ADP + P i FAD FADH 2 Citric acid cycle CoA Acetyle CoA NADH + 3 H + CoA CO 2 Pyruvate (from glycolysis, 2 molecules per glucose) ATP Glycolysis Citric acid cycle Oxidative phosphorylatio n Figure 9.11

28 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.12 Acetyl CoA NADH Oxaloacetate Citrate Malate Fumarate Succinate Succinyl CoA -Ketoglutarate Isocitrate Citric acid cycle SCoA SH NADH FADH 2 FAD GTP GDP NAD + ADP P i NAD + CO 2 CoA SH CoA SH CoA S H2OH2O + H + H2OH2O C CH 3 O OCCOO – CH 2 COO – CH 2 HO C COO – CH 2 COO – CH 2 HCCOO – HOCH COO – CH CH 2 COO – HO COO – CH HC COO – CH 2 COO – CH 2 CO COO – CH 2 CO COO – Glycolysis Oxidative phosphorylation NAD + + H + ATP Citric acid cycle Krebs Cycle: A closer Look

29 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

30 Oxidative phosphorylation: 3 Big Ideas NADH and FADH 2 Donate e - to e - transport chain, which powers ATP synthesis via oxidative phosphorylation Chemiosmosis couples e - transport to ATP synthesis e - from NADH and FADH 2 lose E in steps

31 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Oxidative Phosphorylation At end of the chain e - passed to O 2, forming water H2OH2O O2O2 NADH FADH2 FMN FeS O FAD Cyt b Cyt c 1 Cyt c Cyt a Cyt a 3 2 H I II III IV Multiprotein complexes Free energy (G) relative to O 2 (kcl/mol)

32 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chemiosmosis: The Energy-Coupling Mechanism ATP synthase – Enzyme that actually makes ATP – Energy from e- drives formation of hydrogen concentration gradient. – Potential Energy !!!! INTERMEMBRANE SPACE H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ P i + ADP ATP MITOCHONDRIAL MATRIX

33 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chemiosmosis e - transfer pumps H + f/ mitochondrial matrix to intermembrane space INTERMEMBRANE SPACE H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ P i + ADP ATP MITOCHONDRIAL MATRIX

34 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chemiosmosis Resulting H + gradient – Stores E – Drives chemiosmosis – Referred to as a proton-motive force – E-coupling mechanism, drives cellular work INTERMEMBRANE SPACE H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ P i + ADP ATP MITOCHONDRIAL MATRIX

35 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chemiosmosis and the e - transport chain Oxidative phosphorylation. electron transport and chemiosmosis Glycolysis ATP Inner Mitochondrial membrane H+H+ H+H+ H+H+ H+H+ H+H+ ATP P i Protein complex of electron carners Cyt c I II III IV (Carrying electrons from, food) NADH + FADH 2 NAD + FAD + 2 H / 2 O 2 H2OH2O ADP + Electron transport chain Electron transport and pumping of protons (H + ), which create an H + gradient across the membrane Chemiosmosis ATP synthesis powered by the flow Of H + back across the membrane ATP synthase Q Oxidative phosphorylation Intermembrane space Inner mitochondrial membrane Mitochondrial matrix Figure 9.15

36 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings An Accounting of ATP Production by Cellular Respiration 3 main processes in metabolism Electron shuttles span membrane CYTOSOL 2 NADH 2 FADH 2 2 NADH 6 NADH 2 FADH 2 2 NADH Glycolysis Glucose 2 Pyruvate 2 Acetyl CoA Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis MITOCHONDRION by substrate-level phosphorylation by substrate-level phosphorylation by oxidative phosphorylation, depending on which shuttle transports electrons from NADH in cytosol Maximum per glucose: About 36 or 38 ATP + 2 ATP + about 32 or 34 ATP or Figure 9.16

37 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Transfer not 100% ~ 40% of E in a glucose molecule – Transferred to ATP during cellular respiration, making ~ 36 ATP

38 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

39 Fermentation Glycolysis – Produces ATP w/ or w/o oxygen, aerobic or anaerobic conditions – Glycolysis + reactions that regenerate NAD +, which can be reused by glyocolysis – Two types alcohol and lactic acid

40 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fermentation Glycolysis + reactions that regenerate NAD +, which can be reused by glyocolysis

41 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fermentation Alcohol fermentation – Pyruvate ethanol in two steps, one of which releases CO 2

42 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lactic acid Fermentation Pyruvate reduced by NADH to form lactate as a waste product (Pyruvate oxidizes NADH) OUCH !

43 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fermentation - Cellular Respiration Compared Both use glycolysis to oxidize glucose to pyruvate Differ in final e - acceptor – Aldehyde transition step in alcohol fermentation – Pyruvate in lactic acid fermentation Cellular respiration produces more ATP Tiny Bubble

44 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings You never knew how exciting PYRUVATE was Pyruvate is key juncture in catabolism Glucose CYTOSOL Pyruvate No O 2 present Fermentation O 2 present Cellular respiration Ethanol or lactate Acetyl CoA MITOCHONDRION Citric acid cycle Figure 9.18

45 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Evolutionary Significance of Glycolysis Glycolysis occurs in nearly all organisms Probably evolved before O 2 in the atmosphere

46 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Catabolism Catabolism of various molecules from food Amino acids Sugars Glycerol Fatty acids Glycolysis Glucose Glyceraldehyde-3- P Pyruvate Acetyl CoA NH 3 Citric acid cycle Oxidative phosphorylation Fats Proteins Carbohydrates Figure 9.19 Beta Oxidation 2X more ATP

47 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biosynthesis (Anabolic Pathways) The body uses small molecules to build other substances Some Intermediates of glycoysis and the Krebs Cycle can be used to form amino acids

48 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The control of cellular respiration Glucose Glycolysis Fructose-6-phosphate Phosphofructokinase Fructose-1,6-bisphosphate Inhibits Pyruvate ATP Acetyl CoA Citric acid cycle Citrate Oxidative phosphorylation Stimulates AMP + – – Figure 9.20

49 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2XjCok8

50 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings kdzrd04


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