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Question #47762
The Question
During a recombinant DNA experiment, a foreign gene is inserted into the lacZ gene of a cloning vector. The vector also carries an ampicillin resistance gene (Amp^R). Following transformation into competent E. coli cells, the culture is plated on an agar medium containing ampicillin and X-gal (a chromogenic substrate). Which of the following statements is INCORRECT regarding the subsequent selection process?
Options
- A.
The ampicillin in the medium serves to eliminate non-transformants, allowing only transformed cells to form colonies.
- B.
Non-recombinant transformants will form blue colonies because their lacZ gene remains intact and produces functional β-galactosidase.
- C.
Recombinant transformants will form white colonies due to the insertional inactivation of the β-galactosidase gene.
- D.
The chromogenic substrate X-gal is utilized to differentiate between transformants and non-transformants based on color production.
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
PCR Primer Design|ADA Deficiency Genetic Correction|Gene Therapy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently conflate the terms 'transformants' and 'recombinants'.
Transformation is the uptake of any plasmid (recombinant or empty), selected by antibiotic resistance.
Recombination is the successful insertion of the foreign gene into the plasmid, selected by insertional inactivation (e.g., blue-white screening).
Option D exploits this functional confusion by swapping the roles of the two selectable markers.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | PCR Primer Design |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |