Mitochondrial_electron_transport_chain—Etc4.svg

Chemiosmosis:

The generation of ATP by the movement of H+ across a membrane during cellular respiration. ATP synthase allows protons to pass through the membrane and uses the kinetic energy to phosphorylate ADP, making ATP.

  • The membrane must be impermeable to ions so that a proton concentration gradient can be maintained.
  • Specific transporters allow movement of ions across the membrane.
  • Electron transport through the ETC creates a proton concentration gradient in which the cystolic side of the inner mitochondria membrane has a higher conc of protons.
  • ATP synthase catalyzes ADP phosphorylation driven by the movement of protons across the inner membrane from the cytosol to the matrix.
  •  NAD and FAD are carriers pass electrons to the ETC in the inner mitochondrial membrane, which in turn pass them to other proteins in the ETC. The energy available in the electrons is used to pump protons from the matrix across the inner mitochondrial membrane, storing energy in the form of a transmembrane electrochemical gradient.
  • The protons move back across the inner membrane through the enzyme ATP synthase.
  • The flow of protons back into the matrix of the mitochondrion via ATP synthase provides enough energy for ADP to combine with inorganic phosphate to form ATP.
  • The electrons and protons at the last pump in the ETC are taken up by oxygen to form water.

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