Which feature of mitochondria supports their role as ATP factories?

Core Concept

The electron-transport chain and ATP synthase are embedded in the inner mitochondrial membrane, much of which is folded into cristae. Electron transport helps establish the proton-motive force across that membrane, and ATP synthase uses the gradient to make ATP. It is more precise to say oxidative phosphorylation occurs across the inner membrane than that it occurs 'entirely on cristae.'