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Production of ATP by Oxidative Phosphorylation



Most of the ATP of Cell is produced in the Mitochondria. This a complex and multi-step process. The following is an attempt to step through this process.

The Role of Hydrogen in the Process

Coenzymes NAD+ and FAD act as carriers of electrons and protons in the form of Hydrogen atoms to the Electron Transport Chain (ETC).

The following is a diagram of first the reduction of NAD+when it captures atoms from the oxidation of glucose and then the oxidation of NADH + H+ when it releases atom to the ETC. Notice how the is then recycled to pick up more.

The protons and electrons from the Hydrogen atoms are then used to power the proton pump of the electron transport chain.

atoms release protons and electrons


The Krebs Cycle in the Mitochondria Supplies most of the NADH + H+
  • is reduced to by Krebs Cycle
  • releases atoms which release protons and electrons
  • FADH2 is produced and protons are pumped
  • 3rd is produced and is recycled
  • New Krebs cycle begins
  • Complete Process



The Electron Transport Chain (ETC) Produces ATP by Chemiosmosis
  • Inner Membrane Parts
  • releases atoms as
  • Oxidation-reduction reactions in the ETC enzymes
  • ETC pumps to intermembrane space building up an energy gradient.
  • Oxygen is the final electron acceptor which produces H2O
  • move down the energy gradient through ATP synthase to produce 3


    • Which Coenzyme Results in the Most Production of ATP in the ETC?
    • How FADH2hands off atoms to the ETC
    • Compare to
    • Did you notice the difference in how many are produced by and Why?



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