Refer to the figure showing an experiment using selectable marker (reporter) gen
ID: 101709 • Letter: R
Question
Refer to the figure showing an experiment using selectable marker (reporter) genes.
Some cells are resistant to ampicillin and sensitive to tetracycline, some are sensitive to both antibiotics, and some are resistant to both. Which of these cell types should be the lowest in proportion in this experiment, and why?
Phenotype for Phenotype for tetracycline BamHl amp tef DNA taken up by amps and tet E co ampicillin BamHl None Sensitive Sensitive oni Foreign DNA only Sensitive Sensitive Foreign DNA pBR322 plasmid Resistant Resistant BamH amp tet pBR322 recombinant Resistant plasmid BamHI Sensitive oniExplanation / Answer
ANSWER: The cell with pBR322 recombinant plasmid containg cells (resistant to ampicillin and sensitive to tetracycline) are in low proportion. - read the below case 4.
Explanation:
Case 1: the Normal cells (do not have any foreign plasmid or DNA). These are present in more number because the intake of foreign DNA is very low rate, the rate in the scence of small number of cell will take the DNA. The cell without any resistant plasmid they are sensitive to both antibiotics.a
Case:2
In the second case they take up the DNA but not get any resistants because the foreign DNA doesn't have any resistant genes. The cell without any resistant genes they are sensitive to both antibiotics.
Case 3:
In this case cells resistant to both the antibiotics (ampicillin & tetracycline) because the presence of normal plasmid is higher than recombinant plasmid the process of recommendation is highly difficult so the these are present in more and more cells can receive this Normal plasmid.
Case 4: the recommendation process rate is very low. The success rate is 1 in 1000. So the less recombinant plasmids present in the solution. Therefore the less the number of cells with this plasmid when compare with all other. Here the foreign DNA interfere the tetracycline gene so the bacteria is sensitive to only tetracycline.