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Question #45921
The Question
Cyanide acts as a lethal respiratory poison by disrupting oxidative phosphorylation. Which of the following statements regarding the cellular consequences of cyanide toxicity is INCORRECT?
Options
- A.
It binds to the Fe3+ of cytochrome a3 in Complex IV, preventing the transfer of electrons to molecular oxygen.
- B.
The formation of metabolic water ceases because oxygen can no longer act as the terminal electron and hydrogen acceptor.
- C.
The pH of the mitochondrial intermembrane space significantly decreases due to the stalling of the electron transport chain.
- D.
The cell undergoes rapid cytoplasmic acidosis due to a compensatory shift towards anaerobic glycolysis to regenerate NAD+.
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
Cytochrome_c_oxidase|Complex_IV|Metabolic_Water_Formation|Terminal_Electron_Acceptor
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often associate 'cyanide poisoning' and 'respiratory failure' with 'acidosis' (which is true systemically due to lactic acid accumulation).
However, they fail to apply the Chemiosmotic Hypothesis to the specific micro-location of the intermembrane space.
The IMS is normally highly acidic due to active proton pumping.
When the ETC stalls, proton pumping stops, and the IMS pH increases (becomes less acidic), creating a high-yield location/quantitative trap.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Metabolic Water Formation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |