The role of O2 in electron transport In mitochondrial electron transport, what is the direct role of O2? a)to provide the driving force for the synthesis of ATP from ADP and Pi b)to function as the final electron acceptor in the electron transport chain c)to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle d)to provide the driving force for the production of a proton gradient.