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Question #45117
The Question
A researcher creates a transgenic mouse by microinjecting a bacterial cDNA encoding a metabolic enzyme into a fertilized egg. Molecular analysis confirms successful nuclear integration and abundant mRNA transcription. However, the synthesized protein is misfolded and completely non-functional. Given that the genetic code is nearly universal and the enzyme requires no post-translational modifications, which of the following is the most scientifically accurate explanation for this anomaly?
Options
- A.
The bacterial cDNA contained introns that the mammalian spliceosomes failed to excise, altering the primary structure.
- B.
Extreme codon bias in the bacterial gene led to ribosomal pausing due to rare tRNA depletion in the mouse, disrupting co-translational folding.
- C.
Microinjection directly into the cytoplasm prevented the transgene from utilizing the host's nuclear chaperones for proper folding.
- D.
The universality of the genetic code only applies to eukaryotes, resulting in a completely different amino acid sequence being translated.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Microinjection Specificity|Analogous Organ Structure|Genetic Code Degeneracy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often conflate the 'universality of the genetic code' (which ensures the same amino acid sequence is theoretically possible) with 'translational efficiency' (which depends on species-specific codon bias and tRNA abundance).
The trap also tests the fundamental NCERT facts that cDNA lacks introns (eliminating Option A) and that microinjection in animals targets the nucleus (eliminating Option C).
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 |