Question

Correctly match the Inhibitor with its respective Function in mitochondrial respiration.

 

• A. P-2; Q-1; R-4; S-3
• B. P-2; Q-3; R-1; S-4
• C. P-2; Q-4; R-3; S-1
• D. P-3; Q-1; R-2; S-4

Hint:

Mitochondrial respiration can be selectively inhibited at different stages using specific inhibitors, which helps in studying the function of individual complexes in the electron transport chain.

Answer 1

The Correct Option is A

Step 1: Understand the function of each inhibitor in mitochondrial respiration.

FCCP (P) is an uncoupler that makes the mitochondrial membrane permeable to protons, disrupting the proton gradient and thus inhibiting ATP synthesis. This is characteristic of proton ionophores.

Cyanide (Q) is a potent inhibitor of mitochondrial respiration, specifically inhibiting cytochrome c oxidase (Complex IV), which is the final enzyme in the electron transport chain.

Oligomycin A (R) inhibits ATP synthase, blocking the production of ATP by preventing protons from flowing back through the ATP synthase complex, thus inhibiting oxidative phosphorylation.

Butyl malonate (S) blocks mitochondrial uptake of succinate, which is a substrate for Complex II in the electron transport chain.

Step 2: Match the inhibitors with their functions.

P - 2: FCCP makes the membrane permeable to protons.
Q - 1: Cyanide inhibits cytochrome c oxidase.
R - 4: Oligomycin A inhibits ATP synthase.
S - 3: Butyl malonate blocks mitochondrial uptake of succinate.

Thus, the correct answer is \( \boxed{(A)} \).