In order to create the energy required to synthesize ATP, ATP synthase must pump hydrogen ions, or protons, from the intermembrane space of the mitochondria into the matrix space. Clicking on each of the thumbnail images will bring up a larger, labeled version of the described scene.

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	First, a proton from the intermembrane space enters the ATP synthase complex.
	Next, another proton leaves the ATP synthase complex and exits into the matrix space.
	Finally, the upper portion of the ATP synthase complex rotates slightly to prepare for the next set of protons to enter and exit the complex.

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