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Question #45122
The Question
A researcher attempts to develop a nematode-resistant tobacco plant by directly bombarding pre-synthesized double-stranded RNA (dsRNA) triggers into the leaf cells using a biolistic gene gun, bypassing the standard Agrobacterium vector method. Despite successful cellular entry, the plant fails to exhibit RNA interference (RNAi) against Meloidogyne incognita. Which of the following best explains the molecular failure of this delivery method?
Options
- A.
High-velocity shear forces fragment the dsRNA, disrupting the structural motifs required for Dicer recognition and subsequent RISC loading.
- B.
Plant cells lack endogenous Dicer enzymes and can only process dsRNA if the genes are stably integrated into the host genome via Agrobacterium.
- C.
Direct bombardment localizes the dsRNA exclusively in the cytoplasm, whereas RISC complex assembly and mRNA silencing strictly occur in the nucleus.
- D.
The gold or tungsten microparticles irreversibly bind to the target nematode mRNA, preventing the complementary binding of the antisense RNA strand.
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
Biolistics/Gene Gun Physics|RNAi Vector Source
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' lies in integrating the biophysical limitations of the Gene Gun (NCERT Ch 11) with the molecular requirements of the RNAi pathway (NCERT Ch 12).
Students often memorize 'Gene Gun is for plants' and 'RNAi is for nematode resistance' and assume they can be seamlessly combined.
This question tests the deeper understanding that RNAi is highly dependent on the structural integrity of dsRNA for Dicer-substrate recognition, which is destroyed by the mechanical shear stress of biolistic delivery.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Biolistics/Gene Gun Physics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |