Question

Question: The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

1. oxygen
2. water
3. NAD⁺
4. pyruvate

Short answer

1. The option “oxygen” is false.
2. The option “water” is false.
3. The option "NAD⁺” is true.
4. The option “pyruvate” is false.

Step-by-step solution

Metabolism

Metabolism is divided into two phases of reactions, which are catabolism and anabolism. The former involves the breakdown of complex molecules. The latter consists of the synthesis of larger molecules.

Explanation of option ‘(A)’

Electron transporter is a series of step that involves the transfer of electron. There is a need for some molecule that receives the electron produced in the electron transport process. Oxygen molecules act as a terminal electron acceptor in ETC.

Thus, oxygen is the final electron acceptor during the process of aerobic oxidative phosphorylation.

Therefore, the given statement is false.

Explanation of option ‘(B)’

The water is produced in the electron transport chain process after accepting electrons and protons by the oxygen—the combining of electron and proton and oxygen results in the formation of water as a final product.

Thus, water is a product produced in this process but does not act as an electron acceptor.

Therefore, the given statement is false.

Explanation of option ‘(C)’

The role of NADH is seen in the process of fermentation that takes place in the absence of oxygen. In this process, the NADH tends to donate an electron to pyruvate and forms the NAD⁺.

Thus, NAD⁺is not the component involved in aerobic oxidative phosphorylation.

Therefore, the given statement is true.

Explanation of option ‘(D)’

Pyruvate accepts the electron in the anaerobic respiration that occurs in the absence of oxygen. This process is not efficient as the aerobic process.

Thus, pyruvate is not the electron acceptor in the aerobic mechanism.

Therefore, the given statement is false.