1. Below is a map of a plasmid called pBR322: (Cannot figure out how to post the
ID: 253227 • Letter: 1
Question
1. Below is a map of a plasmid called pBR322:
(Cannot figure out how to post the picture)
Suppose that the pBR322 plasmid is cleaved with the restriction enzyme PstI. Suppose a PstI-digested segment of mouse DNA is then ligated into the PstI site in pBR322. This recombinant DNA molecule is then used to transform E. coli cells. a. Which antibiotic should be added to the medium to select for cells that have incorporated a recombinant plasmid? b. How can you explain the presence of bacterial colonies that are resistant to both antibiotics? c. You decide to digest your recombinant DNA molecule with BamHI and EcoRI and then analyze the digested recombinant DNA molecule on an agarose gel. How many bands will you see on the gel? d. You decide to digest your recombinant DNA molecule with BamHI and PstI and then analyze the digested recombinant DNA molecule on an agarose gel. How many bands will you see on the gel? ?a. Which antibiotic should be added to the medium to select for cells that have incorporated a recombinant plasmid?
b. How can you explain the presence of bacterial colonies that are resistant to both antibiotics?
c. You decide to digest your recombinant DNA molecule with BamHI and EcoRI and then analyze the digested recombinant DNA molecule on an agarose gel. How many bands will you see on the gel?
d. You decide to digest your recombinant DNA molecule with BamHI and PstI and then analyze the digested recombinant DNA molecule on an agarose gel. How many bands will you see on the gel?
Explanation / Answer
ans 1- to select recombinants, cell must be grown in media containing tetracycline. the recombinants will be resistant to the tetracycline and sensitive to the ampicillin as the DNA is inserted at the ampR site of plasmid.
ans 2- the cell has not taken up the foreign DNA or the cell may have the foreign DNA but at the different site than these selective marker genes.
ans 3- three bands will be obtained after digestion with bamH1 and ecoR1
ans 4- four bands will be obtained after digestion with pstI+BamH1
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.