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Question #45428
The Question
A patient who recently underwent an organ transplant is administered a bioactive molecule produced by the fungus Trichoderma polysporum. During a routine follow-up, the patient exhibits mild hypocalcemia and reduced bone demineralization, despite having elevated serum Parathyroid Hormone (PTH) levels. Which of the following best explains this physiological paradox?
Options
- A.
The molecule inhibits calcineurin, suppressing both T-cell activation and the NFAT-dependent differentiation of osteoclasts, thereby blunting the bone-resorbing action of PTH.
- B.
The molecule acts as a competitive inhibitor of PTH receptors on osteoblasts, directly preventing the release of osteoclast-stimulating factors.
- C.
The molecule stimulates the parafollicular cells of the thyroid gland to secrete calcitonin, which strongly antagonizes the hypercalcemic effect of PTH.
- D.
The molecule competitively inhibits HMG-CoA reductase, indirectly reducing the synthesis of steroid-derived hormones essential for calcium absorption.
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
Parathyroid_Gland|Osteoclast_Activity|Cyclosporin_A|T-cells
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating knowledge from 'Microbes in Human Welfare' (Cyclosporin A) with 'Chemical Coordination' (PTH/Calcium homeostasis) via a shared intracellular signaling pathway.
The trap in Option D tests multiple NCERT facts simultaneously: confusing the fungal sources (Trichoderma vs Monascus) and the chemical nature of hormones (PTH is a peptide, not a steroid).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Calcium Homeostasis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |