Question

Plasmid pBR322 has PstI restriction enzyme site within gene ampR that confers ampicillin resistance. If this enzyme is used for inserting a gene for β-galactoside production and the recombinant plasmid is inserted in an E.coli strain

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

Answer 1

Answer: (B)

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

Answer 2

Plasmid pBR322 contains the ampR gene that confers ampicillin resistance. If the PstI restriction enzyme site within the ampR gene is used to insert a gene for β-galactosidase, it will disrupt the ampR gene, rendering the plasmid incapable of conferring ampicillin resistance to the host cell. This means that the transformed cells will no longer have the ability to resist ampicillin.

So, the correct option is (B): it will not be able to confer ampicillin resistance to the host cell.