<prompt> Complex-I in electron transpo chain is ?NADH - CoQ reductaseCoQ - cytochrome C reductaseCytochrome-C oxidaseNone of the above  <response>: Ans. is a i.e., NADH - CoQ reductase Components of ETC are :?Complex I NADH - CoQ reductase catalyzes the transfer of electron from NADH to coenzyme Q CoQ.Complex II Succinate - CoQ reductase or succinate dehydrogenase transfers electrons from succinate to coenzyme Q.Complex III CoQ - cytochrome C reductase, transfers electron from CoQ to cytochrome C.Complex IV cytochrome C oxidase transfers electrons from cytochrome C to 02. 