Define plasmid. Describe the structure and utility of the plasmids.
Define plasmid. Describe the structure and utility of the plasmids.

Plasimids are tiny extranuclear circular DNAs found in bacteria and fungi that carry extra chromosomal genes. For example, pBR 322, pUC-18. Plasmids are 2700 bp long and have features such as a selectable marker and cloning site.