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Question #45143
The Question
A diagnostic laboratory uses an ELISA kit designed to detect a specific parasitic surface glycoprotein (antigen) in patient serum. Over a few years, the kit begins yielding a high rate of false-negative results in patients who are clinically symptomatic and confirmed positive via PCR. Which of the following is the most scientifically accurate explanation for this diagnostic failure?
Options
- A.
The parasite underwent rapid antigenic drift, altering the conformational structure of its surface glycoprotein, thereby preventing binding with the kit's specific antibodies.
- B.
The parasite evolved to secrete proteases into the host serum that degrade the peroxidase enzyme conjugated to the kit's antibodies during the assay.
- C.
The host's immune system developed tolerance and stopped producing antibodies against the parasite, rendering the antigen-antibody interaction in ELISA impossible.
- D.
The parasitic genome mutated, preventing the complementary single-stranded DNA probes in the ELISA kit from hybridizing with the target sequence.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
ELISA|Evolutionary Ecology of Parasitism|Antibody-Antigen Interaction
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' lies in distinguishing the molecular targets of different diagnostic tools (ELISA targets proteins/antigens via antibodies; PCR targets nucleic acids) and understanding how Darwinian evolution (antigenic drift) specifically impacts protein-based immunodiagnostics.
Students often fall for the 'Functional Confusion' trap by mixing up ELISA components with molecular probes (Option D) or misunderstanding the difference between detecting antigens vs. host antibodies (Option C).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology and Its Applications - Class 12 |
| Concept | Molecular Diagnosis by ELISA |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |