Why can cells function so efficiently under anaerobic conditions? I don't understand
any of this. Please help
Cells that can function under anaerobic conditions have enzymes that enable them to "ferment."
As you know, anaerobic means without oxygen. Oxygen is needed as the terminal electron acceptor in the electron transport chain at the inner mitochondrial membrane in order to allow the oxidative phosphorylation process to occur so that lots of ATP can be made from the reduced cofactors, NADH and FADH2.
Without oxygen, oxidative phosphorylation stops and no more ATP ...