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Question #46280
The Question
A researcher extracts genomic DNA from Nicotiana tabacum to isolate a specific floral gene. After purifying the DNA from inhibitory alkaloids, the target gene is excised using the restriction endonuclease EcoRI. Simultaneously, the cloning vector pBR322 is digested with BamHI. The researcher mixes the digested vector and insert with T4 DNA ligase, transforms the mixture into competent E. coli, and plates them for selection. Which of the following accurately predicts the outcome of the antibiotic selection process?
Options
- A.
Recombinant colonies will grow on ampicillin-containing medium but fail to grow on tetracycline-containing medium due to insertional inactivation.
- B.
Transformant colonies will grow on both ampicillin and tetracycline-containing media because non-compatible sticky ends prevent recombinant formation, favoring vector self-ligation.
- C.
No colonies will grow on either medium because the restriction enzymes EcoRI and BamHI both cleave within the AmpR gene, destroying all antibiotic resistance.
- D.
Recombinant colonies will grow on tetracycline-containing medium but fail to grow on ampicillin-containing medium due to the specific cleavage pattern of EcoRI.
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
Solanaceae Floral Formula|Restriction Endonuclease Nomenclature|pBR322 Selection Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often blindly apply the concept of 'insertional inactivation' (assuming cloning into BamHI automatically disrupts TetR) without verifying the prerequisite step.
The trap relies on the fundamental NCERT rule that successful ligation requires compatible sticky ends generated by the same restriction enzyme.
Failing to recognize the nomenclature/source difference (EcoRI vs BamHI) leads to the false assumption that a recombinant plasmid was formed.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Solanaceae Floral Formula |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |