A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell's chromosomal DNA. Plasmids naturally exist in bacterial cells, and they also occur in some eukaryotes.

The pGLO plasmid also contains a gene encoding for beta-lactamase. Beta-lactamase is an enzyme that will allow transformed bacteria to be resistant to antibiotics that have a beta-lactam ring. Thus, ...