What does plasmid mean?
A plasmid is a small DNA molecule, usually circular, that can replicate independently of a cell's main chromosome. Plasmids occur naturally in bacteria and may contain genes providing advantages such as antibiotic resistance, virulence, or the ability to metabolize unusual substances. They can move between bacterial cells, making them important in both evolution and the spread of antibiotic resistance. Researchers also use engineered plasmids as vectors to introduce selected DNA into cells. The term is central to cloning, gene editing, recombinant DNA technology, and molecular biology. Although plasmids are most characteristically bacterial, related genetic elements are found in other organisms, and laboratory plasmids may be designed with features such as selectable markers and multiple cloning sites.
nounA small, usually circular DNA molecule that replicates independently of a cell's chromosomal DNA, typically within bacteria. Plasmids may carry genes that confer traits such as antibiotic resistance and can be transferred between cells.
- A circular, extrachromosomal DNA molecule that can replicate independently within a host cell, especially a bacterium, and may carry accessory genes such as those for antibiotic resistance.
"The researchers inserted a fluorescent gene into a bacterial plasmid and introduced it into the cells."
"Scientists commonly use plasmids to deliver selected genes into bacterial cells in the laboratory."
"The bacterium acquired a plasmid that made it resistant to an antibiotic used in the patient's treatment."
The plural is formed by adding -s.
"The laboratory maintains a collection of plasmids for gene manipulation."
A plasmid can act like a tiny ring of transferable DNA, carrying useful genes through bacterial cells.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does plasmid come from?
The word plasmid was formed in the early twentieth century from Greek plasma, meaning something formed or molded, together with the suffix -eid, meaning resemblance or form. The terminology was developed as biologists sought to describe genetic material existing apart from the cell nucleus or chromosome. Its relatives include plasm, plasma, and words such as plastic, all connected with the Greek root meaning to mold or form.
How plasmid is actually used
In biology, the term is used mainly for small DNA molecules that exist separately from the host chromosome. In molecular biology and biotechnology, 'plasmid' is also used for engineered DNA vectors, even when the experimental construct is linear rather than circular.
Easily confused with plasmid
A plasmid is a DNA molecule that replicates independently, whereas a plasm is the living substance of an organism or cell.