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Question #45891
The Question
In a eukaryotic transcription unit, a point mutation occurs in the template (non-coding) strand, specifically altering the DNA sequence that transcribes the highly conserved 5' GU dinucleotide of the first intron. Which of the following statements correctly describes the most likely downstream consequence of this mutation?
Options
- A.
The spliceosome will fail to recognize the 5' splice site, leading to intron retention and the likely synthesis of a truncated protein due to a premature stop codon.
- B.
RNA polymerase II will stall at the mutated site, leading to premature termination of the primary transcript and nonsense-mediated decay.
- C.
The mutation will alter the reading frame of the coding strand, causing the ribosome to skip the mutated exon during translation.
- D.
SnRNPs will utilize the complementary sequence on the coding strand to restore the correct splice site during post-transcriptional modification.
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|Non-Coding Strand|Introns
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' lies in distinguishing the distinct roles and substrates of RNA Polymerase II versus the Spliceosome.
A common misconception is that mutations in a gene sequence will halt transcription itself.
However, splice site mutations specifically disrupt post-transcriptional RNA processing (splicing), leaving transcription intact but ultimately ruining translation by introducing intronic sequences that act as frameshifts or premature stop codons.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Non-Coding Strand Utility |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |