Here's how it works:

1. Electron transport chain: Electrons are passed from molecule to molecule down a chain of proteins embedded in the inner mitochondrial membrane.

2. Proton gradient: As electrons move through the chain, they release energy that pumps protons (H+) from the mitochondrial matrix to the intermembrane space. This creates a proton gradient across the membrane.

3. ATP synthase: The proton gradient drives the rotation of ATP synthase, an enzyme that uses the potential energy stored in the gradient to convert ADP (adenosine diphosphate) and inorganic phosphate (Pi) into ATP.

Therefore, electron transport is crucial for ATP production, which is the primary energy currency of the cell.