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Question #46319
The Question
During strenuous skeletal muscle activity, localized accumulation of H+ ions initially facilitates oxygen unloading from oxyhaemoglobin via the Bohr effect. However, if severe intracellular acidosis persists, it acts as a metabolic failsafe, shutting down the primary ATP-generating pathway active under these conditions. Which of the following enzymes is directly inhibited by this acidosis, and what is the physiological rationale?
Options
- A.
Hexokinase; to prevent the complete exhaustion of cellular glycogen and glucose reserves.
- B.
Phosphofructokinase; to prevent lethal cellular acidification by halting further glycolysis and lactate production.
- C.
Pyruvate kinase; to reverse the glycolytic pathway and immediately initiate gluconeogenesis in the muscle.
- D.
Cytochrome c oxidase; to reduce the production of metabolic water and prevent osmotic swelling of the cell.
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
TCA_Cycle_Stoichiometry|Glycolysis_Redox_Balance|Bohr_Effect
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often study the Bohr effect (Breathing and Exchange of Gases) and Glycolysis (Respiration) in isolation.
The trap is failing to connect that the exact same chemical trigger (H+ ions) that maximizes O2 delivery at the tissue level eventually acts as a negative feedback inhibitor on the glycolytic pacemaker (PFK).
This demonstrates a critical homeostatic tradeoff: the cell sacrifices ATP production to prevent fatal intracellular acidosis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Breathing and Exchange of Gases - Class 11 |
| Concept | Haldane Effect vs. Bohr Effect |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |