Chemiosmosis / ATP Synthesis

  1. Electron transport chain - Machinery: 
    • * Four Enzymes in the mitochondrial inner membrane:
    • -NaDH
    • -Bc1 complex
    • -Cytochrome oxidase complex
    • - Succinate dehydrogenase 

    • *Two electron carriers
    • - Ubiquinone and cytochrome C 
  2. Electron transport chain 
    NADH and FADH2 need to be converted to ATP

    Where: inner membrane of the mitocondria

    • How: 
    • -NADH and FADH2 = oxydized n allow transporters to pump H+ across membrane
    • - Generate electrical current ( charge / across the membrane from H+ being pump out of mitochondria)
    • - H+ flow through ATP synthase 

  3. Chemiosmosis 
    • NADH and FADH2 both donate 2e-
    • NADH -> NADH dehydrogenase 
    • FADH -> bc1 complex 

    These high-energy e- re transferred from complexes w low e- affinity (NADH dehydrogenase) to those w higher affinity (cytochrome oxidase complex)
  4. Chemiosmosis 
    Reduction of complexes allows H+ to be pumped out of matrix to inner membrane space, creating a charge gradient and Hgradient.

    Succinate dehydrogenase (last step of energy harvest II in krebs) reduces ubiquinone using FADH2 as an electron carrier.
  5. ATP Synthase 
    Fis a rotor that is powered by H+. Rotation turns Fi through a stator.  

    • Fi has a 3alpha n 3beta subunits.
    • sub units bind ADP and Pi- force them together to make ATP ( lose, tight, open conformation)  

    • Fi creates ATP as it turns. 
    • - 3.33 ATP per revolution or 10H+
  6. Aerobic respiration 
    • Oxygen is the terminal electron acceptor in the cytochrome oxydase 
    • - produces water (oxygen oxydize and water reduce) 
  7. Aerobic respiration 
    • Methanogens (archaea)
    • - reduce CO2 to methane 
    • - Habitat: 1/3 of human's intestines, landfills and swamps

    • Sulfate-resducing bacteria (SRB)
    • - reduce sulfate to hydrogen sulfide 
    • - sour gas 
Card Set
Chemiosmosis / ATP Synthesis
Unit 2