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Question #45110
The Question
A researcher develops a transgenic tobacco plant expressing a double-stranded RNA (dsRNA) construct homologous to the tumor-inducing genes of the T-DNA from Agrobacterium tumefaciens. When this plant is infected by a wild-type, virulent Agrobacterium, which of the following accurately describes the molecular sequence of events and the cellular outcome?
Options
- A.
The T-DNA fails to integrate into the plant genome because the dsRNA triggers the degradation of the incoming Ti plasmid.
- B.
The T-DNA integrates and transcribes mRNA, but translation is prevented as the RISC complex degrades the target mRNA, resulting in a normal phenotype.
- C.
The T-DNA integrates into the genome, but the dsRNA directly binds to the promoter region of the T-DNA, causing transcriptional gene silencing.
- D.
The T-DNA integrates and produces functional oncoproteins, but the RNAi pathway neutralizes these proteins post-translationally, preventing crown gall disease.
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
Ti-Plasmid|dsRNA|RNAi_Mechanism|mRNA_Degradation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between genomic integration/transcriptional success and functional expression.
A common misconception among students is that 'resistance' implies the pathogen's DNA fails to enter or integrate into the host.
In the RNAi mechanism (as taught in NCERT for Meloidogyne incognita), the foreign genes are present and transcribed, but the expression is intercepted at the mRNA stage (Post-Transcriptional Gene Silencing).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Agrobacterium Tumefaciens Mechanism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |