GATE ES 2023 | Question: 7

Question

A student wants to decide electron acceptor for aerobic, facultative and anaerobic bacteria. In this context, read the following statements

i. Dissolved Oxygen (DO) can act as electron acceptor for aerobic bacteria

ii. Nitrite can act as electron acceptor for aerobic bacteria.

iii. Dissolved Oxygen (DO) can act as electron acceptor for anaerobic bacteria.

iv. Nitrite can act as electron acceptor for facultative bacteria.

The correct choice is

• A. (i) is correct; (iv) is correct
• B. (ii) is correct; (iii) is incorrect
• C. (ii) is correct; (iii) is correct
• D. (i) is correct; (ii) is correct

Answer 1

i. Dissolved Oxygen (DO) can act as an electron acceptor for aerobic bacteria. This statement is correct because aerobic bacteria use oxygen as the final electron acceptor in their metabolic processes.ii. Nitrite can act as an electron acceptor for aerobic bacteria. This statement is incorrect. Nitrite is not a typical electron acceptor for aerobic bacteria; oxygen is the primary electron acceptor for them.iii. Dissolved Oxygen (DO) can act as an electron acceptor for anaerobic bacteria. This statement is incorrect. Anaerobic bacteria thrive in the absence of oxygen and use alternative electron acceptors like nitrate, sulfate, or carbon compounds.iv. Nitrite can act as an electron acceptor for facultative bacteria. This statement is correct. Facultative bacteria are versatile and can switch between aerobic and anaerobic modes of metabolism. In anaerobic conditions, some facultative bacteria can use nitrite as an electron acceptor.Therefore, (i) is correct, (ii) is incorrect, (iii) is incorrect, and (iv) is correct.