This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Complex-I in electron transpo chain is ? 
Select and explain. 
A. NADH - CoQ reductase, B. CoQ - cytochrome C reductase, C. Cytochrome-C oxidase, D. None of the above
A: NADH - CoQ reductase
Answer: A: NADH - CoQ reductase 
Explanation: 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.