Question

Which of the following are inhibitors of electron transport chain?
A. Rotenone
B. Amobarbital
C. Piericidin A
D. Chlorpromazine
E. Atractyloside
Choose the most appropriate answer from the options given below

• A. A, B, C, E
• B. A, B, C, D
• C. B, C, D, E
• D. A, C, E

Hint:

ETC Complex I Inhibitors: Rotenone, Piericidin A, Amytal (Amobarbital), Chlorpromazine. Complex III = Antimycin A. Complex IV = Cyanide, CO, Azide.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Mitochondrial respiration inhibitors target specific electron carriers within respiratory complexes I, II, III, or IV.

Step 2: Detailed Explanation:
Analyzing the mitochondrial inhibitors:
1. A. Rotenone, B. Amobarbital (Amytal), C. Piericidin A, D. Chlorpromazine: All act as direct inhibitors of Complex I (NADH-Q oxidoreductase NADH dehydrogenase), blocking electron transfer from iron-sulfur centers ($N-2$) to ubiquinone ($Q$).
2. E. Atractyloside: An inhibitor of the Adenine Nucleotide Translocase (ANT ATP-ADP translocase), not a direct electron carrier inhibitor of the electron transport chain complexes.
Thus, A, B, C, and D are direct inhibitors of the electron transport chain.

Step 3: Final Answer:
Therefore, the inhibitors of the electron transport chain are A, B, C, D, corresponding to option (B).