Question

E.coli having $pBR322$ with $DNA$ insert at BamHI site cannot grow in medium containing tetracycline. Recognition site for BamHI is present in $tet^R$ region of $pBR322$.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

If both assertion and reason are true and reason is the correct explanation of assertion

Answer 2

$pBR322$ has recognition sites for several commonly used restriction enzymes. Recognition site for BamHI is present in tetr region i.e., region responsible for tetracycline resistance. When an insert is added at the BamHI recognition site the gene for tetracycline resistance becomes non-functional and the recombinant bacteria with plasmid $pBR322$ that has $DNA$ insert at BamHI lose tetracycline resistance.