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Question #45894
The Question
During gene expression in a eukaryote, a mutation causes a spliceosome error, allowing an aberrantly spliced mRNA to escape into the cytoplasm. The cell utilizes RNA interference (RNAi) as a secondary surveillance mechanism to prevent the translation of this non-functional isoform. Which of the following statements regarding this process is INCORRECT?
Options
- A.
RNAi acts as a Post-Transcriptional Gene Silencing (PTGS) mechanism that degrades the target mRNA in the cytoplasm.
- B.
The source of the complementary dsRNA triggering this defense can be mobile genetic elements (transposons) that replicate via an RNA intermediate.
- C.
The RNA-induced silencing complex (RISC) binds to the aberrant transcript and transports it back to the nucleus for re-splicing.
- D.
This specific method of cellular defense is universally present in all eukaryotic organisms.
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
Spliceosome Mechanics|RNA Interference (RNAi) Mechanism|RNAi Vector Source
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Spatial compartmentalization of the Central Dogma.
Students often confuse the roles and locations of different RNA processing machineries.
The trap relies on the misconception that aberrant cytoplasmic mRNA can be 'fixed' by returning it to the nucleus.
In reality, nuclear export is generally unidirectional for mRNA, and cytoplasmic surveillance mechanisms like RNAi act by degrading the transcript (quality control), not repairing it.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Spliceosome Mechanics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |