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Do the Krebs cycle and electron transport chain require ATP?

  1. Dec 22, 2015 #1
    I cannot find a website that answers this question, and all diagrams I see do not show that ATP is used. Does this mean that these processes are intrinsically spontaneous? I can see how the electron transport chain is spontaneous, as the oxidation of oxygen to water is favorable (E 1/2=0.7V).
  2. jcsd
  3. Dec 23, 2015 #2

    Andy Resnick

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    The electron transport chain *produces* ATP, it does not consume ATP. It is spontaneous in the sense that H moves along the pH gradient (the membrane potential) to provide the energy, but creating the membrane potential requires consumption of NADH, produced by the Krebs cycle, which consumes sugar (pyruvate) as the energy source.
  4. Dec 23, 2015 #3

    Thank you!
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