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Question #45902
The Question
In an experimental cell line, a point mutation in the gene encoding Valyl-tRNA synthetase abolishes the function of its editing domain, causing it to lose its specificity. Which of the following will be the most direct consequence of this mutation during gene expression?
Options
- A.
The ribosome will recognize the mischarged tRNA and halt translation, leading to premature chain termination.
- B.
The mutated synthetase will alter the anticodon loop of the tRNA, preventing its binding to the mRNA.
- C.
Structurally similar non-cognate amino acids will be attached to the tRNA and incorporated into polypeptides at valine codons.
- D.
Uncharged tRNA will accumulate in the cytoplasm, directly inhibiting the peptidyl transferase activity of the 23S rRNA.
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
Aminoacyl-tRNA Synthetase|ATP|Cognate tRNA
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The 'Adaptor Hypothesis' and Ribosomal Blindness.
Students often mistakenly believe that the ribosome proofreads the actual amino acid attached to the tRNA.
The critical trap is failing to recognize that translational fidelity is entirely dependent on the aminoacyl-tRNA synthetase during the charging phase; once mischarged, the error is inevitably incorporated into the protein.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | tRNA Charging Accuracy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |