Use the following to answer questions :
A plasmid has genes that confer resistance to both ampicillin and tetracycline.Foreign DNA is inserted at a restriction enzyme recognition site that lies within the ampicillin gene.
-After host cells have been given the opportunity to take up the plasmid,which type of cells should be the rarest?
A) Bacteria with no plasmid and no foreign DNA
B) Bacteria with the foreign DNA but no plasmid
C) Bacteria with the recombinant plasmid
D) Bacteria with the nonrecombinant plasmid
E) All types should appear with approximately the same frequency.

Question

Quizplus · Accepted Answer

Since the foreign DNA is inserted within the ampicillin gene, bacteria with the recombinant plasmid will not be resistant to ampicillin. Therefore, they will be killed off by ampicillin during selection, making them the rarest type of cells. All other types of cells should appear with approximately the same frequency.

Use the Following to Answer Questions