What is ubiquinone ?
Ubiquinone, is an electron acceptor in the Electron transport chain. It is found in the inner membrane of mitochondria. It recieves electron from NAD dehydrogenase (complex I) and also from the FADH2 (complex II).
The reduced ubiquinone (ubiquinol) is oxidised by transferring of electrons to cytochrome c via cytochrome bc1 complex (complex III).