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Oxidative Phosphorylation

Oxidative Phosphorylation. Step 3. Overview.

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Oxidative Phosphorylation

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  1. Oxidative Phosphorylation Step 3

  2. Overview • The spatial arrangement of electron carriers built into the inner membrane makes it possible for the mitochondrion to use chemical energy released by redox reactions to create an H+ gradient and then use the energy stored in that gradient to drive ATP synthase. • Occurs across the inner membrane (cristae) • Produces up to 34 ATP

  3. 0 • 6.10 Most ATP production occurs by oxidative phosphorylation • Electrons from NADH and FADH2 • Travel down the electron transport chain to oxygen, which picks up H+ to form water • NADH is oxidized as the first protein complex is reduced • FADH2 is oxidized while the first electron carrier is reduced. • Energy released by the redox reactions • Is used to pump H+ into the space between the mitochondrial membranes (active transport)

  4. . H+ H+ H+ H+ H+ Protein complex H+ H+ ATP synthase H+ Electron carrier H+ Intermembrane space Inner mitochondrial membrane FADH2 FAD Electron flow 1 +2 O2 H+ NAD+ 2 NADH H+ H+ Mitochondrial matrix + P ATP ADP H+ H2O H+ Chemiosmosis Electron Transport Chain OXIDATIVE PHOSPHORYLATION 0 • In chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes • Driving the synthesis of ATP  TURBINE ATPSynthase Turbine

  5. The Final Acceptor • One oxygen atom will accept two electrons and form water with two hydrogen. ATPSynthase Turbine Overall Video CH 25

  6. Oxidative Phosphorylationin four steps 1. Electron carrying molecules release e- • NADH  protein complex 1 • FADH2 electron carrier 1 2. H+ ions from matrix are actively transported by pumps across the membrane into the inter membrane space. 3. e- are transported to Oxygen to form water 4. Chemiosmosisallows H+ ions to diffuse through ATP synthase in order to create ATP

  7. Cyanide, carbon monoxide Rotenone Oligomycin H+ H+ H+ ATPSynthase H+ H+ H+ H+ H+ H+ DNP FAD FADH2 1 + O2 2 H+ NADH NAD+ 2 H+ + ATP P ADP H+ H2O H+ Electron Transport Chain Chemiosmosis 0 CONNECTION • 6.11 Certain poisons interrupt critical events in cellular respiration • Various poisons • Block the movement of electrons • Block the flow of H+ through ATP synthase • Allow H+ to leak through the membrane Figure 6.11

  8. Review CR • Each molecule of glucose yields up to 38 molecules of ATP • Each NADH molecule produces 3 ATP • Each FADH2molecule produces 2 ATP Total 10 NADH =30 2 FADH2 =4 4 ATP produced in steps 1 and 2 38

  9. 2 2 NADH 2 2 NAD+ NADH NAD+ GLYCOLYSIS P 2 ADP + 2 ATP 2 2 Pyruvate 2 Lactate Glucose 0 Fermentation: Anaerobic Respiration • Under anaerobic conditions, many kinds of cells Can use glycolysis alone to produce small amounts of ATP • In lactic acid fermentation • NADH is oxidized to NAD+ as pyruvate is reduced to lactate Figure 6.13A

  10. NADH NAD+ 2 NAD+ NADH 2 2 2 GLYCOLYSIS 2 ADP + 2 CO2 released 2 P 2 ATP 2 Ethanol Glucose 2 Pyruvate Figure 6.13B 0 • In alcohol fermentation • NADH is oxidized to NAD+ while converting pyruvate to CO2 and ethanol Figure 6.13C

  11. Two Types of Fermenting Organisms • Strict anaerobes • Facultative Anaerobes

  12. 0 INTERCONNECTIONS BETWEEN MOLECULAR BREAKDOWN AND SYNTHESIS • 6.14 Cells use many kinds of organic molecules as fuel for cellular respiration

  13. Food, such aspeanuts Carbohydrates Fats Proteins Sugars Fatty acids Amino acids Glycerol Aminogroups OXIDATIVEPHOSPHORYLATION(Electron Transportand Chemiosmosis) CITRICACIDCYCLE AcetylCoA Pyruvate Glucose G3P GLYCOLYSIS ATP 0 • Carbohydrates, fats, and proteins can all fuel cellular respiration • When they are converted to molecules that enter glycolysis or the citric acid cycle EX: fats G3P and 2 carbon intermediates Figure 6.14

  14. ATP needed to drive biosynthesis ATP GLUCOSE SYNTHESIS CITRIC ACID CYCLE Acetyl CoA Glucose Pyruvate G3P Amino groups Fatty acids Amino acids Sugars Glycerol Carbohydrates Proteins Fats Cells, tissues, organisms 0 • 6.15 Food molecules provide raw materials for biosynthesis • Cells use some food molecules and intermediates from glycolysis and the citric acid cycle as raw materials to make the 3 classes of macromolecules our cells need to function • This CONSUMES ATP Figure 6.15

  15. 0 • 6.16 The fuel for respiration ultimately comes from photosynthesis • All organisms • Can harvest energy from organic molecules • Plants, but not animals • Can also make these molecules from inorganic sources by the process of photosynthesis Figure 6.16

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