The byproducts of most catabolic processes are NADH and [FADH2] which are the reduced forms. Metabolic processes use NADH and [FADH2] to transport electrons in the form of hydride ions (H-). These electrons are passed from NADH or [FADH2] to membrane bound electron carriers which are then passed on to other electron carriers until they are finally given to oxygen resulting in the production of water. As electrons are passed from one electron carrier to another hydrogen ions are transported into the intermembrane space at three specific points in the chain. The transportation of hydrogen ions creates a greater concentration of hydrogen ions in the intermembrane space than in the matrix which can then be used to drive ATP Synthase and produce ATP (a high energy molecule).