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Question #46748
The Question
Cyanide is a potent toxin that induces histotoxic hypoxia by binding to the copper centers of Complex IV (Cytochrome c oxidase) in the Electron Transport System. Which of the following events is NOT a physiological consequence of this inhibition in highly active tissues like the myocardium?
Options
- A.
Complete cessation of metabolic water synthesis in the mitochondrial matrix.
- B.
Collapse of the proton motive force across the inner mitochondrial membrane.
- C.
Continued oxidation of NADH + H⁺ at Complex I to sustain the TCA cycle.
- D.
Accumulation of reduced cytochrome c on the outer surface of the inner mitochondrial membrane.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Mitochondria|ETS Complex Specificity|Metabolic Water Formation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot & Retrograde Inhibition: Students often memorize that Cyanide stops ATP synthesis but fail to trace the retrograde domino effect on the ETS.
A common misconception is that upstream complexes (like Complex I) can continue functioning independently for a while.
However, the ETS is a tightly coupled, sequential pathway; a block at the terminal end fully reduces all intermediate carriers, immediately halting upstream NADH oxidation.
Additionally, Option D serves as a 'Location Trap' to test the exact NCERT line regarding the position of Cytochrome c.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell – The Unit of Life - Class 11 |
| Concept | Mitochondrial Endosymbiotic Evidence |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |