This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
Role of molecular oxygen in ETC is 
Select and explain. 
A. Transfer of reducing equivalent to CoQ, B. Transfer of reducing equivalent from cytosol to mitochondria, C. To act as electron acceptor, D. Generation of ATP
C: To act as electron acceptor
Answer: C: To act as electron acceptor 
Explanation: As it turns out, the reason you need oxygen is so your cells can use this molecule during oxidative phosphorylation, the final stage of cellular respiration. ... Oxygen sits at the end of the electron transpo chain, where it accepts electrons and picks up protons to form water