plasmid (redirected from F-pili)

plasmid /plas·mid/ (plaz´mid) an extrachromosomal self-replicating structure of bacterial cells that carries genes for a variety of functions not essential for cell growth and that can be transferred to other cells by conjugation or transduction. See also episome.

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F plasmid  a conjugative plasmid found in F+ (male) bacterial cells that leads with high frequency to its transfer, and much less often to transfer of the bacterial chromosome, to an F- (female) cell lacking such a plasmid.

R plasmid , resistance plasmid a conjugative factor in bacterial cells that promotes resistance to agents such as antibiotics, metal ions, ultraviolet radiation, and bacteriophages.

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plas·mid (plzmd)

n.

A circular, double-stranded unit of DNA that replicates within a cell independently of the chromosomal DNA and is most often found in bacteria; it is used in recombinant DNA research to transfer genes between cells. Also called extrachromosomal element.

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plasmid,

n a type of intracellular inclusion considered to have a genetic function.

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plasmid

an extrachromosomal self-replicating genetic element of a cell. In bacteria, plasmids are circular DNA molecules that reproduce themselves and are thus conserved, apart from the chromosome, through successive cell divisions; they include the F factor and R factor.

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R factor plasmid

see R factor.

relaxed plasmid

occurs in tens to several hundred copies per bacterium and are dependent solely on host enzymes for replication.