Question

Which one of the following matches is CORRECT between the inhibitors given in Group A with their modes of action in Group B? 
\[\begin{array}{|c|c|} \hline Group A & Group B \\ \hline \text{(P) Antimycin A} & \text{(i) Inhibits cytochrome c oxidase} \\ \hline \text{(Q) Amytal} & \text{(ii) Blocks electron transfer from cyt b to cyt c1} \\ \hline \text{(R) Carbon monoxide} & \text{(iii) Inhibits adenine nucleotide translocase} \\ \hline \text{(S) Atractyloside} & \text{(iv) Prevents electron transfer from Fe-S centers of complex 1 to ubiquinone} \\ \hline \end{array}\]
 

• A. P: ii, Q: iv, R: i, S: iii
• B. P: iii, Q: iv, R: ii, S: i
• C. P: iv, Q: iii, R: ii, S: i
• D. P: ii, Q: iv, R: iii, S: iv

Hint:

Inhibitors of the electron transport chain, such as Antimycin A and Amytal, target different components of the pathway, disrupting ATP synthesis.

Answer 1

The Correct Option is A

Step 1: Understanding the inhibitors and their mechanisms.
- P: Antimycin A inhibits cytochrome c oxidase, part of the electron transport chain (mode iv).
- Q: Amytal blocks electron transfer from cytochrome b to cytochrome c1 (mode iii).
- R: Carbon monoxide inhibits cytochrome c oxidase (mode ii).
- S: Atractyloside prevents electron transfer from Fe-S centers of complex I to ubiquinone (mode i).

Step 2: Conclusion.
The correct answer is (C) as it matches each inhibitor with its correct mechanism of action.