Before You Begin
Question #45147
The Question
Following the introduction of an invasive alien species into a freshwater lake, ecologists monitoring the native fish population for a specific endemic viral pathogen using a standard indirect ELISA observe a sudden, massive spike in positive results. However, the native fish exhibit zero clinical symptoms of the viral disease. Which of the following best explains this diagnostic anomaly?
Options
- A.
A. The alien species secretes proteases that degrade the primary antibodies, leading to non-specific binding of the enzyme-linked secondary antibody.
- B.
B. Proteins from the alien species share high sequence homology and identical epitopes with the endemic pathogen, causing cross-reactivity with the diagnostic antibodies.
- C.
C. The invasion has induced a severe allergic response in the native fish, elevating IgE levels which directly catalyze the chromogenic substrate in the ELISA.
- D.
D. The alien species has integrated its genetic material into the native fish, altering the complementary DNA probe hybridization during the ELISA protocol.
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
ELISA|Alien Species Invasion Impacts|Antigenic Cross-Reactivity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Understanding the molecular basis of ELISA (epitope recognition) and distinguishing it from nucleic acid hybridization.
The primary trap lies in Option D, which tests the student's ability to separate protein-based diagnostics (ELISA) from nucleotide-based diagnostics (Probes/PCR).
It also tests the application of ecological shifts (alien species) causing molecular cross-reactivity (false positives) due to shared homologous structures.
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 |