Answer to Question #317409 in Genetics for Jaruhe

Question

We transformed E coll cells with a plasmid modified to contain a 'virulence factor' which would allow growth on media containing the antibiotic

kanamycin (an). The plasmid confers constitutive resistance to ampicillin (Amp).

Assume you were given competent cells of known transformation efficiency (TE). Assume TE= 1x10[6] (note 10[6) means 10 to the power of 5).

You want to have about 1000 colonies on the P-200 plate. How many nanograms of plasmid should you use in the transformation reaction? Select

only one answer.

Answer 1

Adding an antibiotic resistance gene to the plasmid solves both problems at once – it allows a scientist to easily detect plasmid-containing bacteria when the cells are grown on selective media, and provides those bacteria with a pressure to keep your plasmid.