1. Complex II does not pump protons, so succinate oxidation misses out on the 4 protons that NADH dehydrogenase (complex I) pumps when it oxidises the NADH derived from malate oxidation.
  2. Glutathione is an antioxidant, and is used by glutathione peroxidase to scavenge hydrogen peroxide.
  3. Chemiosmotic comparisons:

    Character

    Archaea

    Purple bacteria

    Chloroplasts

    Mitochondria

    Energy source

    Light

    Light

    Light

    NADH

    Pump

    Bacteriorhodopsin

    Bacterial photosystem, cytochrome-b/c

    Photosystems I and II, cytochrome b/f

    Complexes I, III and IV

    Products

    ATP

    ATP

    ATP, NADPH, oxygen

    ATP, water
  4. Antimycin-A blocks electron transfer from UQH2 to cyt-c. Therefore reduced ubiquinol would accumulate.
  5. Valinomycin is a K+ ionophore. By moving these ions across the inner membrane, it destroys the charge gradient component of the PMF.