Selection of Transformed Cell

Q. What is the role of tetracyclin resistant gene in plasmid vector?

1. Improves the stability of the plasmid
2. Gives tertacyclin immunity against accidental antibiotic presence
3. Helps to identify the cells that are transformed
4. Increases the ability of plasmid to accomodate gene of interest

Q. Some foreign DNA fragment is attached to Cla I site of pBR322. This recombinant vector is used to transition Escherichia coli host cells. The cells subjected to transformation are plated on two different media-one containing ampicillin and the other containing tetracycline. The transformed cells containing the recombinant vector

1. will grow on both tetracycline containing and ampicillin containing media
2. will not grow on either tetracycline containing or ampicillin containing media
3. will not grow on tetracycline, but not on ampicillin-containing media
4. will grow on ampicillin but not on tetrecycline-containing media