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Question #46781
The Question
A patient suffering from severe emphysema develops massive hypercapnia. Clinical tests reveal a normal platelet count and normal levels of circulating inactive clotting factors, yet the patient exhibits severe coagulopathy (bleeding tendency). Based on the principles of gas transport and enzyme kinetics, which of the following statements correctly explains the molecular basis of this phenomenon?
Options
- A.
Excessive CO2 competitively binds to the active site of thrombokinase, preventing the conversion of prothrombin to thrombin.
- B.
The resulting respiratory acidosis alters the ionization state of the catalytic amino acid residues in clotting enzymes like thrombin, disrupting their activity.
- C.
The enhanced chloride shift (Hamburger phenomenon) actively sequesters Ca2+ ions into RBCs, depriving the clotting cascade of its essential cofactor.
- D.
High pCO2 permanently denatures the tertiary structure of fibrinogen, rendering it unable to form a cross-linked fibrin network.
Check Your Answer
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
Amino Acid Zwitterion Equilibrium | Clotting Cascade Factors | Chloride Shift (Hamburger Phenomenon)
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Respiratory Physiology (Hypercapnia/Acidosis) with Biomolecules (Enzyme kinetics/pH optimum) and Circulation (Coagulation cascade).
Students often memorize these systems in isolation.
The primary trap (Option C) uses the 'Chloride shift' buzzword, which is highly relevant to hypercapnia, tricking students into assuming a false mechanism involving calcium depletion.
The question tests the deep understanding that systemic pH changes directly compromise the active site chemistry of circulating enzymes.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biomolecules - Class 11 |
| Concept | Amino Acid Zwitterion Equilibrium |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |