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Question #45365
The Question
The activation of mammalian acrosomal enzymes (e.g., acrosin) during fertilization and the activation of Bacillus thuringiensis (Bt) Cry protein in an insect gut both rely on the localized conversion of an inactive precursor into an active lytic agent. If a mutant bollworm develops resistance to Bt cotton by secreting a specific molecule in its midgut that acts analogously to the protease inhibitors found in mammalian seminal plasma (which prevent premature acrosomal activation), which of the following steps in Bt toxin action is directly blocked?
Options
- A.
Solubilization of the protoxin crystals by the alkaline pH of the midgut.
- B.
Proteolytic cleavage of the inactive protoxin into the active toxin.
- C.
Binding of the active toxin to specific receptors on the midgut epithelial cells.
- D.
Creation of pores in the midgut epithelial cells leading to osmotic lysis.
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
Hyaluronidase|Bt-Toxin|Alkaline pH
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line 'alkaline pH activates Bt toxin' without realizing the nuance: alkaline pH only solubilizes the crystal, whereas actual activation requires proteolytic cleavage by gut enzymes.
This question tests the ability to distinguish between solubilization (pH-driven) and activation (protease-driven) by applying a cross-chapter analogy of zymogen regulation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Acrosomal Enzyme Activation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |