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Question #47666
The Question
During strenuous exercise, skeletal muscle cells experience localized hypoxia and shift to anaerobic respiration. Which of the following statements correctly explains the primary biochemical reason why the oxidative decarboxylation of pyruvate (link reaction) ceases under these conditions?
Options
- A.
Accumulation of NADH in the mitochondria allosterically inhibits the Pyruvate Dehydrogenase Complex.
- B.
The absence of oxygen directly inhibits the decarboxylase activity of the link reaction enzymes.
- C.
Lactate dehydrogenase in the mitochondrial matrix rapidly converts pyruvate to lactic acid.
- D.
Depletion of ATP prevents the active transport of pyruvate across the inner mitochondrial membrane.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Terminal Electron Acceptor|Pyruvate Decarboxylation Complexity|Fermentation Limitations
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often know that a lack of O2 stops the link reaction and Krebs cycle, but they mistakenly believe O2 directly regulates these steps.
The critical concept is that these pathways are strictly dependent on the continuous regeneration of NAD+ by the ETC.
The question also tests the 'Location Trap' by placing Lactate Dehydrogenase in the mitochondrial matrix instead of the cytoplasm.
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 |