Anaerobic condition refers to an environmental condition where oxygen is absent. In case of Electron Transport System (ETS) and ATP production, oxygen acts as the final acceptor of electrons. As oxygen is a reactant in ETS and ATP production, unavailability of oxygen can cause no oxidation of the coenzymes or the carriers such as NAPH and FADH2 and no ATP will be produced. Thus, both Electron Transport System and ATP production will stop in the absence of oxygen.
