Before You Begin
Question #46505
The Question
A researcher genetically engineers a mouse to express a specific double-stranded RNA (dsRNA) exclusively in its memory B-cells. This dsRNA is perfectly complementary to the mRNA transcripts encoding the immunoglobulin heavy chains. Upon secondary exposure to the specific antigen, which of the following represents the most accurate physiological outcome?
Options
- A.
The humoral response is completely abolished because the dsRNA prevents the V(D)J recombination process at the genomic level.
- B.
The mouse exhibits induced hypogammaglobulinemia due to post-transcriptional gene silencing, even though the genomic sequence for the antibody remains intact.
- C.
The memory B-cells fail to produce antibodies because the dsRNA binds directly to the promoter region of the immunoglobulin gene, blocking transcription.
- D.
A robust secondary immune response occurs because immunological memory overrides translational regulation via rapid alternative splicing.
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
B-lymphocytes|mRNA|RNAi|Active Immunity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently confuse 'Gene Silencing' (RNAi) with 'Gene Knockout' or 'Transcriptional Repression'.
The trap tests the precise understanding that RNAi is strictly a post-transcriptional event that degrades mRNA, creating a 'phenotypic knockout' while leaving the genomic DNA (and thus the cellular 'memory' of the V(D)J recombination) completely intact.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Active vs Passive Immunity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |