Question

Which of the following is the final electron acceptor in the electron transport chain ?
A.$FAD{H_2}$
B.$NADH$
C.Cytochrome C
D.Water
E.Oxygen

Answer 1

Hint: The electron transport chain is built up of peptides , enzymes and other molecules . The transfer of electrons from electron donors to electron acceptors take place via redox reactions in this chain .

Complete step by step answer:
Electron transport chain is a metabolic pathway through which the electron travels from one carrier or acceptor to another . It is present in the inner mitochondrial membrane.
Electrons produced during the citric acid cycle are oxidised and transferred to ubiquinone.
From here the electrons are transferred to Cytochrome c.
When the electrons are passed through one carrier to another they are coupled to an enzyme for the synthesis of ATP from ADP and inorganic phosphate.
Now comes oxygen which acts as the final hydrogen or electron acceptor.
Although the aerobic process necessarily requires oxygen , the amount of oxygen is much less and the role of oxygen is limited to the last step of the whole chain.
However, the role of oxygen is vital since it drives the whole process by removing hydrogen from the chain.
The electrons, after getting transferred to ${O_2}$ , result in the formation of water $({H_2}O)$ .
Hence, option E is correct , oxygen is the final electron acceptor in the electron transport chain .


Note:
The electron transfer chain is the most important stage of cellular respiration from an energy point of view as it produces the most amount of ATP .Energy is released in the redox reactions .