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Question #47669
The Question
An arctic mammal, exhibiting Allen's Rule, relies heavily on non-shivering thermogenesis to maintain its core body temperature in sub-zero climates. Which of the following cellular adaptations involving the carbon pathway and mitochondrial function best explains its ecological fitness?
Options
- A.
Increased flux through the Pyruvate Dehydrogenase Complex in the mitochondrial matrix, paired with high proton conductance through uncoupling proteins in the inner membrane.
- B.
Increased activity of the Pyruvate Dehydrogenase Complex in the cytoplasm, coupled with a highly efficient ATP synthase to maximize metabolic heat.
- C.
Decreased pyruvate decarboxylation to conserve glucose, shifting the metabolic burden to anaerobic lactic acid fermentation for rapid heat dissipation.
- D.
Complete bypass of the link reaction, allowing pyruvate to be directly oxidized by the cytochrome bc1 complex to generate heat.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Ecological Fitness (Darwinian Fitness)|Pyruvate Decarboxylation Complexity|Allen’s Rule and Surface-to-Volume Ratio
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often harbor the misconception that 'metabolic efficiency' always equals 'maximum ATP yield'.
In the context of ecological fitness in extreme cold, evolutionary selectivity favors uncoupling the proton gradient from ATP synthase to produce heat (sacrificing ATP).
The question also tests the precise cellular location of the Link Reaction (matrix) via the trap in Option B (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 |