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Question #45407
The Question
During an experimental gene therapy, RNA interference (RNAi) is utilized to silence a dominant mutant allele in human multipotent hematopoietic stem cells. However, an off-target effect occurs where the introduced siRNA inadvertently targets the mRNA of a critical cell-surface receptor required for normal cellular differentiation. Which of the following represents the most accurate molecular consequence of this event?
Options
- A.
Translational silencing occurs in the cytoplasm via the RISC complex, preventing receptor synthesis and causing the stem cells to fail in lineage commitment.
- B.
The siRNA-RISC complex enters the nucleus and binds to the receptor gene's promoter, directly blocking RNA polymerase and halting transcription.
- C.
The off-target silencing permanently alters the genetic code of the stem cell, a mutation that will be inherited by all subsequent daughter cells.
- D.
The accumulation of the degraded mRNA fragments acts as a retroviral template, triggering reverse transcription and immediate apoptosis.
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
Stem Cells|RNA Interference (RNAi) Mechanism|ADA Deficiency Genetic Correction
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently confuse 'gene silencing' via RNAi with 'gene mutation' or 'transcriptional blocking'.
The trap lies in understanding that RNAi (as taught in NCERT Biotechnology) is strictly a post-transcriptional event occurring in the cytoplasm, affecting mRNA stability and translation, rather than altering the DNA or blocking transcription directly.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Differentiation of Stem Cells |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |