All members of the microbial world contain plasmids, which in most cases code for unknown functions. Plasmids vary in size, copy number, host range, their genetic composition, and their ability to be transferred to other cells. One of the most important plasmids is the R plasmid, which codes for resistance to various antimicrobial medications and heavy metals.
■ What single function must all plasmids encode?
■ What functions must a plasmid code for in order to be self-transmissible?
■ What does the phrase, "reservoir for R plasmids'' mean when referring to plasmids carried by non-disease-causing bacteria?
■ Do you think it would be easier to cure a bacterium containing high- or low-copy-number plasmids? Explain.
Was this article helpful?