The following images attempt to illustrate
how ATP synthase produces ATP and emphasize the key steps in this
process. Clicking on each of the thumbnail images will bring
up a larger, labeled version of the described scene.
see the Flash movie for the following sequence of images,
A key site of ATP
synthesis is the mitochondria.
Here we see ATP synthase,
along with other complexes, embedded in the inner
membrane of the mitochondria.
Notice the proton gradient
formed by the high concentration of hydrogen ions
above the inner membrane and the lower concentration below
ADP and Pi
are now visible. These molecules are the substrates for ATP
A hydrogen ion, or proton, enters the
ATP synthase complex.
The upper part of the ATP synthase complex
rotates as each new proton enters the complex.
After the upper portion of the complex
has rotated three times, ADP and Pi are combined by the lower
portion of the complex to form ATP.