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Question #46494
The Question
Both Plasmodium and Bacillus thuringiensis are associated with the release of specific toxic substances (haemozoin and Bt-toxin, respectively) that cause severe physiological disruptions in their targets. Which of the following statements comparing these two substances is INCORRECT?
Options
- A.
Bt-toxin is an exogenous protoxin requiring an alkaline pH shift for activation, whereas haemozoin is an endogenous metabolic byproduct of the parasite.
- B.
Activated Bt-toxin causes cell swelling and lysis by creating pores in the midgut epithelium, whereas haemozoin directly induces the lysis of human erythrocytes to facilitate merozoite release.
- C.
Haemozoin is formed from the degradation of host hemoglobin, while Cry proteins are synthesized as inactive intracellular crystals during the bacterial sporulation phase.
- D.
The clinical symptoms caused by haemozoin are mediated by the host's immunological inflammatory response, whereas Bt-toxin directly targets and destroys specific insect epithelial cells.
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
Plasmodium|Bacillus thuringiensis|Midgut Epithelium|Haemozoin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Cause vs.
Effect in Cytolysis.
Students frequently confuse the consequence of RBC lysis (the release of haemozoin) with the actual cause of the lysis (intracellular multiplication of merozoites).
Furthermore, they may falsely equate the direct, receptor-mediated cytolytic mechanism of Bt-toxin with the indirect, immune-mediated pathogenesis of haemozoin.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Haemozoin Release |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |