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Question #45754
The Question
Both the activation of Bacillus thuringiensis (Bt) protoxin in target insects and the phenomenon of glycosuria in humans represent 'threshold-dependent biological gating'. Which of the following statements accurately differentiates the physiological basis of these two threshold events?
Options
- A.
The Bt toxin threshold is achieved via acidic solubilization in the foregut, whereas glycosuria occurs when the secretion capacity of the distal convoluted tubule is exceeded.
- B.
The Bt toxin threshold relies on an alkaline pH-induced structural cleavage in the midgut, whereas glycosuria occurs due to the kinetic saturation of carrier proteins in the proximal convoluted tubule.
- C.
Both thresholds are determined by the maximum transport rate (Tm) of specific membrane receptors located on the epithelial lining of their respective organs.
- D.
The Bt toxin threshold is a concentration-dependent saturation of midgut pores, whereas glycosuria is a pH-dependent failure of glucose reabsorption in the Loop of Henle.
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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
Renal_Threshold|Bt_Toxin_Activation_Trigger|pH_Dependent_Transport
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between a qualitative/structural threshold (pH-dependent protoxin cleavage) and a quantitative/kinetic threshold (carrier protein saturation).
The question heavily utilizes 'Location Traps' (midgut vs foregut, PCT vs DCT) and 'Process Traps' (secretion vs reabsorption, acidic vs alkaline), which are high-frequency pitfalls in NEET Biology.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Renal Threshold Concept |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |