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Question #45116
The Question
A researcher successfully microinjects a transgene into a eukaryotic cell. Genomic integration is confirmed. Later, it is observed that the transgene is actively transcribed, producing both sense and antisense RNAs. However, Western blotting reveals that the target protein is completely absent in the cell. Which of the following mechanisms best explains this failure of expression?
Options
- A.
The sense and antisense RNAs hybridize to form dsRNA, which triggers post-transcriptional silencing via the RNAi pathway.
- B.
The host cell's restriction endonucleases recognize the foreign mRNA and degrade it before translation can occur.
- C.
The presence of antisense RNA induces heavy methylation of the transgene promoter, causing transcriptional silencing.
- D.
The sense and antisense RNAs competitively bind to the smaller subunit of ribosomes, blocking the initiation of translation.
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
Microinjection Specificity|RNA Interference (RNAi) Mechanism|RNAi Vector Source
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Understanding that successful DNA integration and transcription do not guarantee protein expression if innate cellular defenses (like RNAi) are triggered.
The trap relies on students confusing the targets of restriction enzymes (DNA vs RNA) or failing to distinguish between transcriptional silencing (preventing RNA synthesis) and post-transcriptional silencing (degrading synthesized RNA).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Microinjection Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |