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Question #46843
The Question
In the epithelial cells of an exocrine gland, tight junctions perform the critical function of preventing leakage across the tissue. If a targeted mutation selectively destroys these tight junctions, the gland exhibits a complete cessation of fluid secretion, despite having normal ATP levels and intact secretory vesicles. Which of the following is the primary cellular mechanism responsible for this secretory collapse?
Options
- A.
Loss of apico-basal polarity allows basolateral Na+/K+ pumps to diffuse to the apical membrane, destroying the directional electrochemical gradient required for osmotic fluid secretion.
- B.
Without tight junctions, the secreted fluid continuously leaks through the paracellular space back into the blood, creating an illusion of secretory failure.
- C.
The mutation indirectly deactivates the Na+/K+ ATPase by uncoupling it from ATP hydrolysis, halting primary active transport across the epithelium.
- D.
The loss of tight junctions physically prevents the formation of gap junctions, halting the intercellular calcium signaling required for synchronized exocytosis.
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
Epithelial Junctions Polarity|Glandular Secretion Mechanism|Active vs Passive Gradient Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line that 'tight junctions prevent leakage' (Option B trap) but fail to synthesize their secondary, equally vital role: maintaining cell polarity (the 'fence' function).
By restricting ion pumps to specific membrane domains, tight junctions are an absolute prerequisite for the directional electrochemical gradients that drive active transport and secretion.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Epithelial Junctions Polarity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |