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Question #47495
The Question
A researcher designs an RNAi vector to confer systemic resistance in a transgenic plant against a specific DNA virus by targeting its mRNA. Despite successful vector integration and active RISC complex formation in the host cytoplasm, the integrated viral genome remains intact and dormant within the host nucleus, completely evading RNAi-mediated degradation. Which of the following best explains this defensive 'stasis' of the viral genome?
Options
- A.
The viral genome has integrated into euchromatin, leading to rapid transcription that saturates the host's Dicer enzymes.
- B.
The viral genome has undergone heterochromatinization, preventing transcription and thus providing no mRNA target for the RISC complex.
- C.
The viral genome lacks a poly-A tail, preventing the binding of the siRNA-RISC complex to its mRNA in the cytoplasm.
- D.
The viral DNA directly binds to the RISC complex in the nucleus, competitively inhibiting the degradation of its own mRNA.
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
Bacteriophage Genetic Material|Ori Sequence Stringency|DNA Polymerase
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in understanding the exact target of RNA interference.
Students often mistakenly assume RNAi directly attacks the viral DNA genome.
By synthesizing NCERT concepts from Biotechnology (RNAi as post-transcriptional silencing) and Molecular Basis of Inheritance (heterochromatin as transcriptionally inactive), the student must deduce that a condensed chromatin state physically prevents mRNA formation, thereby shielding the virus from RNAi machinery.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Bacteriophage Genetic Material |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |