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Question #45186
The Question
A transgenic cotton crop expressing the cryIAc gene is subjected to an unprecedented, prolonged heatwave. Subsequently, ecologists observe a sharp decline in local non-target pollinator populations (such as bees) and note that the surrounding ecosystem fails to progress toward its expected climax community. Based on biomolecular and ecological principles, which of the following best explains this phenomenon?
Options
- A.
Thermal stress alters the three-dimensional conformation of the Cry protein, compromising its strict midgut receptor specificity, leading to pollinator mortality and stalling the progression to a climax community.
- B.
Elevated temperatures induce an alkaline shift in the normally acidic gut of pollinators, prematurely solubilizing the protoxin crystals and causing non-target epithelial lysis.
- C.
Heat-induced denaturation prevents the cleavage of the inactive protoxin by gut proteases, converting it into a broad-spectrum neurotoxin that halts secondary succession.
- D.
Thermal degradation of the plant's genome causes the cryIAc gene to mutate, producing a systemic toxin that bioaccumulates in pollinators, accelerating the ecosystem toward a pioneer stage.
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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
Cry protein|Resource Partitioning|Niche Overlap
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that Bt toxin is strictly target-specific and requires an alkaline pH, but fail to integrate the biomolecular reality that this specificity is entirely dependent on thermolabile protein conformation.
The trap lies in assuming genetic traits (like Bt specificity) are absolute and immune to environmental abiotic factors (like temperature) that govern protein folding, while simultaneously testing the ecological downstream effects (succession) of a molecular failure.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology and Its Applications - Class 12 |
| Concept | Cry Gene Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |