Question

In pbr322,foreign DNA has to be introduced in tet r region from the restrictions tion enzymes give below one should be used and why :pvul ,EcoRL BamHi

Give reason why the other two enzymes cannot be used

Answer 1

Enzyme-BamH 1 should be used to incorporate DNA in tetracycline region. Because,only BamH 1 & Sal 1 are having their recognition sites in tetracycline region.
(Image reference-NCERT Biology pg no-199)
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Answer 2

Enzyme which should be used is Bam HI.

Restriction enzymes are the ones which are used to cleave genetic material. pBR322 is a plasmid vector with tetracycline and ampicillin resistant genes present.

The tetracycline resistant region in this plasmid has restriction sites namely - BamHI and SalI.

From the given options, tetracycline resistant region has only BamHI and hence only this restriction enzyme can be used to insert foreign DNA.

PvuI is present at ampicillin resistant region, hence transformed plasmid will be ampicillin sensitive. EcoRI site is not present at any antibiotic resistant sequence.