What is a plasmid?

Plasmids are small, circular pieces of double-stranded DNA that exist independently of the chromosomal DNA in bacteria and some other cells. They often carry genes that provide beneficial traits, such as antibiotic resistance or the ability to metabolize unusual substances. Plasmids are widely used in genetic engineering and biotechnology as vectors to introduce foreign genes into host organisms. Their ability to replicate independently makes them valuable tools for cloning and gene expression studies.