The final resting place or last electron acceptor of electrons donated by NADH and FADH2 is oxygen (O2). In the electron transport chain, which is the final stage of cellular respiration, electrons are passed along a series of electron carriers, including NADH and FADH2, until they are eventually transferred to oxygen. Oxygen is reduced to water (H2O) in this process, which is the terminal reaction of the electron transport chain. Therefore, oxygen can be considered the final resting place for the electrons that are donated by NADH and FADH2 during cellular respiration.