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Question #45225
The Question
The binding of activated Cry toxins (e.g., Cry1Ac) to the midgut epithelial receptors of the cotton bollworm shares a fundamental molecular prerequisite with the phenomenon of competitive enzyme inhibition (e.g., malonate inhibiting succinate dehydrogenase). Which of the following statements correctly identifies this shared prerequisite while accurately distinguishing the two processes?
Options
- A.
Both processes are strictly governed by structural complementarity to a specific target site; however, competitive inhibition is reversible by increasing substrate concentration, whereas Cry toxin binding initiates irreversible pore formation.
- B.
Both processes involve high-affinity binding that alters the Vmax of the target system; however, Cry toxins require an alkaline pH for solubilization, whereas competitive inhibitors require an acidic environment.
- C.
Both rely on the irreversible displacement of a natural ligand from an active site; however, Cry toxins are activated in the midgut, whereas competitive inhibitors are active in their native state.
- D.
Both processes depend on steric complementarity to allosteric receptors; however, competitive inhibition increases the Km of the enzyme, whereas Cry toxins decrease the Km of gut enzymes.
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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
Competitive Enzyme Inhibition Kinetics|Cry Gene Specificity|Restriction Enzyme Cleavage Physics
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Synthesizing Biomolecules (Enzyme Kinetics) with Biotechnology (Bt Cotton) via the universal principle of structural complementarity.
The trap relies on students confusing the kinetic parameters of competitive inhibition (Vmax vs Km) and the reversibility of the processes.
Option A correctly identifies the shared 'lock-and-key' dynamic while contrasting the reversible metabolic block of the inhibitor with the irreversible toxicological cascade of the Cry protein.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biomolecules - Class 11 |
| Concept | Competitive Enzyme Inhibition Kinetics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |