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Question #47717
The Question
A research team attempts to provide a permanent cure for ADA deficiency by directly introducing a recombinant pBR322 plasmid, carrying a functional human ADA cDNA, into a patient's cultured lymphocytes. They plan to re-infuse these cells without using any viral vectors. Which of the following statements best explains the fundamental genetic flaw in this somatic gene therapy approach?
Options
- A.
The prokaryotic origin of replication (ori) in pBR322 is incompatible with eukaryotic replication machinery, preventing stable inheritance of the plasmid during lymphocyte division.
- B.
Human lymphocytes lack the specific restriction endonucleases required to naturally integrate the circular pBR322 plasmid into their nuclear genome.
- C.
The functional ADA cDNA lacks introns, making it impossible for the eukaryotic spliceosomes to process the transcript, leading to translation failure.
- D.
Selectable markers like ampicillin resistance (AmpR) on pBR322 are only active in germline cells and undergo immediate silencing in differentiated somatic cells.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Thermus aquaticus|Annealing Temperature|Primer Specificity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize pBR322 as a universal vector and forget the taxonomic boundary of the 'ori' sequence.
The trap tests the distinction between extrachromosomal autonomy in bacteria versus the requirement for viral integration (or eukaryotic origins) in mammalian cells.
Failing to recognize that prokaryotic replication machinery is incompatible with eukaryotic nuclear replication leads to selecting incorrect distractors.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Plasmid vs Chromosomal DNA |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |