Question

A DNA sequence of interest was digested and ligated into the middle of the AmpR gene region of pBR322 vector. The vector also contains a TetR gene which is not interrupted. After introducing the recombinat DNA into bacterial cells, the resulting transformants were tested on a variety of media. Which of the following results would be expected? Group of answer choices Growth on tetracyclin containing media. Death on media containing both tetracyclin and ampicillin. Growth on media containing both tetracyclin and ampicillin. Growth on ampicillin containing media.

Answer 1

Transformed E. coli cells with the DNA sequence inserted into the AmpR gene of pBR322 would be expected to grow on tetracycline-containing media but not on media with ampicillin or both antibiotics.

Step-by-step explanation:

In this scenario, where a DNA sequence has been inserted into the pBR322 vector disrupting the AmpR gene, the transformed E. coli cells would exhibit specific growth patterns on media containing antibiotics. Since the AmpR gene is interrupted, the cells would not be resistant to ampicillin anymore, but they would still retain resistance to tetracycline due to the intact TetR gene. Therefore, we would expect the cells to grow on tetracycline-containing media but not on ampicillin-containing media, and they would certainly not grow on media containing both antibiotics.

Answer 2

The following two results are possible:

Option A "Growth on tetracyclin containing media." and

Option B "Death on media containing both tetracyclin and ampicillin."

Step-by-step explanation:

Since the TetR gene was not interrupted, the bacteria is resistant to the presence of Tetracyclin antibiotic in the media, so yes, it will grow when there is only tetracyclin present. However, when ampicillin is also introduced, the bacteria can no longer grow since its AmpR gene has been rendered non-functional. It is now no longer resistant to the presence Ampicillin and hence, will not be able to grow in its presence.

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