NEETZoologyBiotechnology - Principles and Processes
A piece of foreign DNA is ligated at the Sal I recognition site of the cloning vector pBR322. The resulting recombinant plasmid is then successfully introduced into E. coli cells. What will be the growth characteristics of the cells transformed with this recombinant plasmid when plated on different antibiotic-containing media?
Options
- AThey will grow on a medium containing tetracycline but fail to grow on a medium containing ampicillin.
- BThey will grow on a medium containing ampicillin but fail to grow on a medium containing tetracycline.
- CThey will grow on media containing both ampicillin and tetracycline.
- DThey will fail to grow on media containing either ampicillin or tetracycline.
Correct answer
B. They will grow on a medium containing ampicillin but fail to grow on a medium containing tetracycline.
Step-by-step solution
In the cloning vector pBR322, the recognition site for the restriction enzyme Sal I is located within the tetracycline resistance gene. When a piece of foreign DNA is ligated at the Sal I site, it causes insertional inactivation of the tetracycline resistance gene. The ampicillin resistance gene remains intact. Therefore, the E. coli cells transformed with this recombinant plasmid will retain resistance to ampicillin but will lose resistance to tetracycline. As a result, they will grow on a medium containing ampici