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Metabolism: Fueling Cell Growth

Metabolism: Fueling Cell Growth. Chapter 6. Preview. Principles of metabolism Metabolism, catabolism, anabolism, energy, redox reaction…. Central metabolic pathway Glycolysis, TCA Respiration Electron transport chain Fermentation. Metabolism.

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Metabolism: Fueling Cell Growth

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  1. Metabolism:Fueling Cell Growth Chapter 6

  2. Preview • Principles of metabolism • Metabolism, catabolism, anabolism, energy, redox reaction…. • Central metabolic pathway • Glycolysis, TCA • Respiration • Electron transport chain • Fermentation

  3. Metabolism Chemical reactions to keep an organism alive. Basic needs

  4. Principles of Metabolism Metabolism is broken down into two components Anabolism Catabolism Catabolism Degradative reactions Reactions produce energy from the break down of larger molecules Anabolism Reactions involved in the synthesis of cell components Anabolic reactions require energy Anabolic reactions utilize the energy produced from catabolic reactions

  5. Metabolic Pathways

  6. Principles of Metabolism TCA Cycle Glycolysis

  7. Energy Definition Free energy-energy released by breaking chemical bonds reactants have more free energy Exergonic reaction products have more energy Endergonic reaction Energy source Compound broken down to release energy Common energy sources

  8. Energy • Oxidizing energy source to release energy Gas +O2 CO2+H2O+energy Glucose+O2 CO2 +H2O +energy Oxidization: gain of oxygen, loss of hydrogen, loss of electron

  9. Harvesting Energy • Oxidation/reduction reactions (redox reactions) electron acceptor electron donor LEO - Lose electrons oxidized GER - Gain electrons reduced • Protons often follow electrons (i.e. a hydrogen atom is extracted/added; e- + H+ = H ) • General rules: • If a compound gains oxygen or loses hydrogen, the reaction is an oxidation • If a compound loses oxygen or gains hydrogen, the reaction is a reduction

  10. “reducing power” Harvesting Energy The role of electron carriers In redox reactions, protons often follow electrons

  11. Harvesting Energy The role of ATP • energy currency Adenosine triphosphate

  12. Harvesting Energy The role of ATP • energy currency

  13. Harvesting Energy Synthesizing ATP • Substrate-level phosphorylation

  14. Harvesting Energy Synthesizing ATP • Substrate-level phosphorylation • Oxidative phosphorylation • Photophosphorylation • Other methods involve an electron transport chain and redox reaction

  15. Principles of Metabolism Synthesizing ATP • Substrate-level phosphorylation • Oxidative phosphorylation - chemical energy is used to create the proton motive force (involves an electron transport chain); the energy of proton motive force is harvested by making ATP; • Photophosphorylation - radiant energy is used to create the proton motive force (involves an electron transport chain); the energy of proton motive force is harvested by making ATP

  16. Central metabolic pathway Central pathways are catabolic and provide • Energy • Reducing power • Precursor metabolites • Central metabolic pathways • Glycolysis • Pentose phosphate pathway • Tricarboxcylic acid cycle

  17. Central Metabolic Pathways Glycolysis (aka Embden-Meyerhoff pathway, glycolytic pathway) glucose 2 pyruvate

  18. Central Metabolic Pathways Glycolysis (aka Embden-Meyerhoff pathway, glycolytic pathway) glucose 2 pyruvate • 2 ATP (net gain) • 2 spent; 4 made • 2 NADH • 6 precursor metabolites

  19. Central Metabolic Pathways Glycolysis (aka Embden-Meyerhoff pathway, glycolytic pathway) glucose 2 pyruvate • 2 ATP (net gain) • 2 spent; 4 made • 2 NADH • 6 precursor metabolites

  20. Central Metabolic Pathways Glycolysis (aka Embden-Meyerhoff pathway, glycolytic pathway) glucose 2 pyruvate • 2 ATP (net gain) • 2 spent; 4 made • 2 NADH • 6 precursor metabolites

  21. Central Metabolic Pathways Pentose phosphate pathway • glucose intermediate of glycolysis • NADPH(amount varies) • 2 precursor metabolites

  22. Central Metabolic Pathways Pentose phosphate pathway • glucose intermediate of glycolysis • NADPH(amount varies) • 2 precursor metabolites Primary role is biosynthesis; ignored in energy-yield calculations;

  23. Central Metabolic Pathways Pentose phosphate pathway • glucose intermediate of glycolysis • NADPH(amount varies) • 2 precursor metabolites Primary role is biosynthesis; ignored in energy-yield calculations;

  24. Central Metabolic Pathways • pyruvate (3 C) acetyl CoA (2 C) + CO2 • (twice per glucose) Transition step

  25. Central Metabolic Pathways • pyruvate (3 C) acetyl CoA (2 C) + CO2 • (twice per glucose) Transition step • NADH • precursor metabolite

  26. Central Metabolic Pathways TCA cycle (aka Kreb’s cycle, citric acid cycle) • acetyl CoA (2 C)  2 CO2 • (twice per glucose)

  27. Central Metabolic Pathways TCA cycle (aka Kreb’s cycle, citric acid cycle) • acetyl CoA (2 C)  2 CO2 • (twice per glucose) • ATP • 3 NADH • FADH2 • 2 precursor metabolites

  28. Central Metabolic Pathways TCA cycle (aka Kreb’s cycle, citric acid cycle) • acetyl CoA (2 C)  2 CO2 • (twice per glucose) • ATP • 3 NADH • FADH2 • 2 precursor metabolites

  29. Central Metabolic Pathways TCA cycle (aka Kreb’s cycle, citric acid cycle) • acetyl CoA (2 C)  2 CO2 • (twice per glucose) • ATP • 3 NADH • FADH2 • 2 precursor metabolites

  30. Glucose (C6H12O6) • Electrons • (protons often follow, therefore H atoms removed) 6 CO2 Review of central metabolic pathway Precursor metabolites ATP (substrate-level phosphorylation) - carried by NADH, FADH2, NADPH Biosynthesis Electron transport chain ATP (oxidative phosphorylation) Glycolysis Pentose phosphate pathway Kreb’s cycle (+ transition step) Oxidation of glucose= Dehydrogenation to CO2+ reducing power (H)

  31. Precursor Metabolites Intermediates of catabolism also used in biosynthesis

  32. Review

  33. Respiration

  34. Electron Transport Chainof mitochondria TCA cycle Electron carrier get recycled Electron transport chain Oxidative phosphorylation Part of figure 3.53

  35. Terminal electron acceptor FADH2 FAD Electron Transport Chainof mitochondria Inside of mitochondria

  36. Creates the proton motive force FADH2 FAD Electron Transport Chainof mitochondria

  37. FADH2 FAD Electron Transport Chainof mitochondria

  38. Electron Transport Chain The Mechanics

  39. Mitochondrial matrix Intermembrane space (inside) (outside) NADH + H+ 2e- 2H+ Electron Transport Chain Hydrogen carrier Electron carrier Hydrogen carrier Electron carrier 2H+ Hydrogen carrier 2H+ Electron carrier

  40. Mitochondrial matrix Intermembrane space (inside) (outside) 2e- 2H+ Electron Transport Chain Hydrogen carrier NAD Regenerates NAD Electron carrier Hydrogen carrier Electron carrier 2H+ Hydrogen carrier 2H+ Electron carrier

  41. Mitochondrial matrix Intermembrane space (inside) (outside) Electron Transport Chain Hydrogen carrier NAD 2H+ Electron carrier 2e- Hydrogen carrier Electron carrier 2H+ Hydrogen carrier 2H+ Electron carrier

  42. Mitochondrial matrix Intermembrane space (inside) (outside) Electron Transport Chain Hydrogen carrier NAD 2H+ Electron carrier Hydrogen carrier 2H+ 2e- Electron carrier Hydrogen carrier 2H+ Electron carrier

  43. Mitochondrial matrix Intermembrane space (inside) (outside) Electron Transport Chain Hydrogen carrier NAD 2H+ Electron carrier Hydrogen carrier 2H+ Electron carrier 2e- Hydrogen carrier 2H+ Electron carrier

  44. Mitochondrial matrix Intermembrane space (inside) (outside) Electron Transport Chain Hydrogen carrier NAD 2H+ Electron carrier Hydrogen carrier 2H+ Electron carrier Hydrogen carrier 2e- 2H+ Electron carrier

  45. Mitochondrial matrix Intermembrane space (inside) (outside) Electron Transport Chain Hydrogen carrier NAD 2H+ Electron carrier Hydrogen carrier 2H+ Electron carrier Hydrogen carrier 2H+ Terminal electron acceptor Electron carrier 2e-

  46. FADH2 FAD Electron Transport Chainof mitochondria

  47. FADH2 FAD Electron Transport Chainof E. coli • Aerobic respiration (shown) • Anaerobic respiration • NO3 as a TEA (different ubiquinol oxidase) • Quinone used provides humans with vitamin K

  48. 12 pairs of electrons (snatched by electron carriers) e- O2 H2O Harvesting Energy The role of electron carriers C6H12O6 + 6 O2 6 CO2 + 6 H2O • Passed to the electron transport chain (used to create the proton motive force); ultimately passed to a terminal electron acceptor (such as O2, making H2O) • Used in biosynthesis (to reduce compounds)

  49. ATP synthase e- O2 H2O Principles of Metabolism Synthesizing ATP • Substrate-level phosphorylation • Oxidative phosphorylation - the energy of proton motive force is harvested; chemical energy is used to create the proton motive force (involves an electron transport chain) ADP + Pi ATP

  50. Harvesting Energy Energy source versus terminal electron acceptor Glucose + 6 O2 6 CO2 + 12 H2O

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