Answer:
Oxidation of NADH2 by coenzyme Q
Step-by-step explanation:
Complex I (NADH-ubiquinone oxidoreductase) is the first enzyme of the electron transport chain, which is located in the inner mitochondrial membrane of eukaryotic cells. The main role of this complex is to oxidize nicotinamide adenine dinucleotide H (NADH) which is donated from glycolysis and the citric acid cycle and transfer 2 electrons from NADH to flavin mononucleotide (FMN). Subsequently, these two electrons are used to reduce Coenzyme Q (i.e. ubiquinone) to ubiquinol. Ubiquinone is a fully oxidized coenzyme Q10, whereas ubiquinol is a fully reduced form of this enzyme.