Question

Bacteria containing recombinant plasmids are often identified by which process?A) examining the cells with an electron microscopeB) using radioactive tracers to locate the plasmidsC) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmidD) removing the DNA of all cells in a culture to see which cells have plasmidsE) producing antibodies specific for each bacterium containing a recombinant plasmid

Answer 1

The correct answer is: C) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid

The plasmids are inserted into bacteria by the process called transformation. Bacteria need to be treated, for example with heat, in order to  take up foreign DNA (recombinant plasmid). A inserted recombinant plasmid contains an antibiotic resistance gene, which allows bacteria to survive in the presence of a specific antibiotic. So, this fact is used for the selection of bacteria that are and are not transformed.