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Question #47715
The Question
In a genetic engineering experiment using the pBR322 vector, a researcher successfully ligates an alien piece of DNA into a unique restriction endonuclease site located exactly within the 'ori' sequence. Following transformation into competent E. coli cells, the culture is plated on an agar medium containing both Ampicillin and Tetracycline. Which of the following will be the most likely outcome?
Options
- A.
No colonies will appear on the agar plate because the disruption of the 'ori' sequence prevents the autonomous replication of the plasmid.
- B.
Recombinant colonies will grow normally because the ampR and tetR genes remain intact and are not subjected to insertional inactivation.
- C.
The transformed cells will grow but will be sensitive to both antibiotics, as the disruption of 'ori' directly inhibits the transcription of resistance genes.
- D.
The plasmid will integrate into the host chromosome to replicate, forming normal colonies that are resistant to both antibiotics.
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
Retroviral Vector|Somatic Cells|Chromosomal DNA
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often mechanically associate 'insertion of alien DNA' exclusively with 'insertional inactivation' of selectable markers (like ampR or tetR).
The trap relies on the student failing to recognize that the 'ori' is the absolute prerequisite for any plasmid function.
If 'ori' is disrupted, the entire vector system collapses, rendering the status of selectable markers completely irrelevant.
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 |