Chapter 19-1

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  1. Overview of oxidative phosphorylation:
    • Catabolism of carbohydrate, lipid, amino acids converge on Cellular Respiration.
    • Involves reduction.
    • Electrons donated by NADH and FADH2.
    • Happens in mitochondria
  2. Overview of photophosphorylation:
    • The process by which sunlight is captured and used to drive ATP synthesis - Absolutely requires light.
    • Involves oxidation of H2O to O2
    • NADP+ is the final electron acceptor
    • Happens in chloroplasts
  3. Nicotinamide Nucleotides:
    NAD+ and NADP+
  4. Flavin Nucleotides:
    FAD and FMN
  5. Universal electron carriers:
    • NAD
    • FAD/FMN
    • Ubiquinone (Coenzyme Q)
    • Cytochromes
    • Iron-Sulfur Proteins
  6. Ubiquinone (coenzyme Q):
    • Lipids-soluble
    • long isoprenoid side-chain
    • vary mobile
    • shuttles electrons between various carriers.
    • Accepts one electron (semiquinone radical) or two (ubiquinol)
  7. Cytochromes:
    • Contain iron-heme groups.
    • Tightly, but non-covalently, associated with the protein.
    • Most are integral proteins of the inner mitochondrial membrane.
    • Three classes.
  8. What are the three classes of cytochromes:
    • Iron protoporphyrin IX (in b-type cytochromes).
    • Heme C (in c-type cytochormes).
    • Heme A (in a-type cytochromes).
  9. Iron-sulfur proteins:
    • Iron is associated with inorganic sulfur or Cys sulfur (not heme sulfur).
    • Participate in one-electron transfers.
    • Rieske iron- sulfur protein iron coordinates with 2 His instead of 2 Cys.
  10. Sequence of electron transport in the respiratory chain:
    • electrons move from NADH, succinate, or other donors to..
    • flavoproteins
    • iron-sulfur proteins
    • Ubiquinone (coenzyme Q)
    • cytochromes (and copper centers)
    • molecular oxygen (final electron acceptor)
  11. ECT complex names:
    • Complex I = NADH dehydrogenase
    • Complex II = succinate dehydrogenase
    • Complex III = cytochrome bc1
    • Complex IV = cytochrome oxidase
  12. P/O ratio:
    Phosphates transferred (P) to oxygens oxidized (O).
  13. NADH P/O:
    2.5 [10 protons pumped out per pair of electrons transferred/ 4 -  number of protons required to drive the synthesis of 1 ATP
  14. Succinate P/O ratio:
    1.5 [ 6 protons pumped – electrons entering the second complex don’t pump 4 protons across like complex one does].
  15. Name some enzymes in mitochondria that can use the products of oxidative phosphorylation as a reactant
    • Enzymes in the mitochondria that can use it as a reactant are isocitrate dehydrogenase,
    • alpha-ketoglutarate dehydrogenase complex, and malate dehydrogenase.
  16. Proton Motive Force:
    • provides energy to
    • drive ATP synthesis. ATP synthesis results from coupling proton flux to phosphorylation. Pumping out H+ generates an electrochemical gradient and the
    • energy is stored as a proton motive force.

    • Two components:
    • Chemical energy potential – due to a H+ chemical gradient across the membrane,
    • and an electrical potential energy – due to a separation of charge (H+).
  17. the Chemiosmotic Hypothesis
    • 1. H+ are pumped to the intermembrane space using the electron transport chain
    • 2. An electrochemical gradient is generated that serves as a proton motive force
    • 3. H+ move down their gradient to generate the force for ATP synthesis
Card Set:
Chapter 19-1
2014-04-28 01:23:41
MCDB 310

MCDB 310- Chapter 19 notes
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