∞ generated and posted on 2016.02.16 ∞
Small(ish) pieces of DNA that persist within lineages of dividing cells.
Plasmids are physically independent of chromosomes and generally also smaller than chromosomes. They contain genes that contribute to a cell's phenotype as well as their own persistence with that cell (including down through the generations).
This video is very basic but does provide a good, if basic, overview of what plasmids are all about. At about the 3:00 min point, it then veers off towards discussing alternative means of cloning:
Many though certainly not all plasmids also their transfer, typically via conjugation, to new cells. The latter are known as both conjugative plasmids and .
Plasmids also serve as important cloning, expression, and shuttle vectors. See also resistance plasmid, Ti plasmid, , and .