noun \ˈplaz-məd\

Definition of PLASMID

:  an extrachromosomal ring of DNA especially of bacteria that replicates autonomously

Origin of PLASMID

plasma + 2-id
First Known Use: 1952


noun \ˈplaz-məd\   (Medical Dictionary)

Medical Definition of PLASMID

: an extrachromosomal ring of DNA that replicates autonomously and is found especially in bacteria—compare episome


noun    (Concise Encyclopedia)

Genetic element not contained within a chromosome. It occurs in many bacterial strains. Plasmids are circular DNA molecules that replicate independently of the bacterial chromosome. They are not essential for the bacterium but may give it a selective advantage. Some plasmids determine the production of proteins that can kill other bacteria; others make bacteria resistant to antibiotics. Plasmids are extremely valuable tools in the fields of molecular biology and genetics, specifically in the area of genetic engineering.


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