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Question #47667
The Question
A specific metabolic poison irreversibly inhibits the Pyruvate Dehydrogenase Complex in the mitochondrial matrix of a eukaryotic cell. Assuming a continuous supply of cytosolic pyruvate and oxygen, which of the following represents the ultimate consequence on the terminal events of the Electron Transport Chain (ETC)?
Options
- A.
Accumulation of protons in the intermembrane space due to the downstream inhibition of ATP synthase.
- B.
Complete cessation of oxygen acting as the final hydrogen acceptor at Cytochrome c oxidase, halting metabolic water formation.
- C.
Uninterrupted generation of the proton motive force driven by alternative electron donation from glycolytic FADH2.
- D.
Enhanced reduction of oxygen at Complex IV to compensate for the loss of mitochondrial substrate-level phosphorylation.
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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
Metabolic Water Formation|Pyruvate Decarboxylation Complexity|Chemiosmotic ATP Synthesis Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Pathway Interdependence.
Students often fail to link the upstream Link Reaction directly to the terminal step of the ETC.
The misconception tested is that oxygen reduction or proton gradients can be maintained independently of the matrix's NADH/FADH2 supply.
It also tests the specific knowledge that metabolic water formation at Complex IV is the ultimate indicator of active oxidative phosphorylation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Pyruvate Decarboxylation Complexity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |