So what process are we ultimately carrying out? Well, as these high energy electrons are moving along the proteins of the electron transport chain, that allows some of these proteins to actually act as proton pumps and pump H plus ions from the matrix of the mitochondria to the intermembrane space. So protein complex one, three, and four actually allow the movement of these H plus ions. So the movement of this electric current allows us to actually pump these H plus ions to the intermembrane space of the mitochondria. And once these electrons end up on protein complex four, this is where we actually use those electrons to actually reduce the diatomic oxygen, the same oxygen that we breathe in from the environment to form the water molecules in the process. Once we generate this proton gradient across the two sides of the membrane, we use another protein complex known as ATP synthase to actually generate those ATP molecules.