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Question #45221
The Question
During an ELISA test for molecular diagnosis of a viral pathogen, a known positive sample yields a false-negative result. It is discovered that a chemical contaminant in the assay buffer caused a conformational distortion in the enzyme linked to the secondary antibody. Which of the following best explains the biochemical basis for the absence of the colorimetric signal?
Options
- A.
The contaminant altered the overall Gibbs free energy change (\Delta G) of the reaction, making the oxidation of the chromogenic substrate non-spontaneous.
- B.
The conformational change prevented the enzyme from lowering the activation energy required to catalyze the oxidation of the chromogenic substrate.
- C.
The contaminant acted as a competitive inhibitor by binding irreversibly to the allosteric site of the linked enzyme.
- D.
The distorted enzyme failed to catalyze the synthesis of primary antibodies, preventing the formation of the antigen-antibody complex.
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
Horseradish_Peroxidase|Antigen-Antibody|Activation_Energy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Biotechnology (ELISA principle) with Biomolecules (Enzyme kinetics).
The trap relies on students confusing the thermodynamic properties of enzymes, mistakenly believing they alter the overall \Delta G of a reaction rather than just the activation energy.
It also tests the precise structural definitions of competitive vs. non-competitive (allosteric) inhibition.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biomolecules - Class 11 |
| Concept | Enzyme Activation Energy Lowering |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |