Question

Plasmid $pBR322$ has PstI restriction enzyme site within gene $a m p^{R}$ that confers ampicillin resistance. If this enzyme is used for inserting a gene for $\beta$-galactoside production and the recombinant plasmid is inserted in an E.coli strain

• A. it will not be able to confer ampicillin resistance to the host cell.
• B. the transformed cells will have the ability to resist ampicillin as well as produce $\beta$-galactoside.
• C. it will lead to lysis of host cell.
• D. it will be able to produce a novel protein with dual ability.

Answer 1

Answer: (A)

it will not be able to confer ampicillin resistance to the host cell.

Answer 2

Since the gene is inserted at Pst I of $a m p^{R}$ region of pBR322, the $a m p^{R}$ gene is inactivated which is called as insertional inactivation. Hence the genetically modified E.coli strain will not be able to confer ampicillin resistance.