ATP synthase is considered a part
of the electron transport chain, but it is not involved in the transport
of electrons. ATP synthase uses the proton gradient created by the
ETC to synthesize ATP. Clicking on each of the thumbnail
images will bring up a larger, labeled version of the described
see the Flash movie for the following sequence of images,
ATP synthase accepts one proton
from the intermembrane space and releases a different proton
into the matrix space to create the energy it needs to synthesize
ATP. It must do this three times to synthesize one ATP from
the substrates ADP and Pi (inorganic phosphate).
With the supply of NADH exhausted, the
electron transport chain can no longer maintain the proton
gradient that powers ATP synthase, and ATP synthesis comes
to a stop.