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Question #46491
The Question
To detect Plasmodium infection during the early stages of low parasitemia, a biotechnology firm developed a PCR-based molecular diagnostic kit. The primers were designed to be complementary to the gene encoding a major merozoite surface protein. However, clinical trials in endemic areas frequently produced false-negative results in patients with active malaria. Which of the following best explains this molecular diagnostic failure?
Options
- A.
High polymorphism in the target gene due to immune selection pressure causes primer-template mismatch and failed annealing.
- B.
The target gene is absent in the sporozoite stage genome, making PCR detection impossible during early liver infection.
- C.
Hemozoin pigment released during the erythrocytic phase irreversibly denatures Taq polymerase during the extension step.
- D.
The merozoite surface protein is an RNA transcript, requiring Reverse Transcriptase PCR (RT-PCR) for successful amplification.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Plasmodium|PCR Primer Design|Molecular Diagnosis by ELISA
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume PCR is a foolproof method for low parasitemia (as per NCERT Biotechnology applications) but fail to integrate the concept of genetic polymorphism and primer specificity.
A common misconception tested here is 'Genomic Equivalence' (Option B) - students often confuse the absence of a protein in a specific life stage with the absence of the gene itself.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Life Cycle of Plasmodium |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |