Microbial Genetic Transfer and Plasmids

Vocabulary flashcards covering bacterial genetics, plasmid types, and mechanisms of horizontal gene transfer such as transformation and conjugation.

Chromosome

The main genetic element in prokaryotes and eukaryotes.

Plasmid

Nonessential, circular, double-stranded DNA that is 1–5% the size of a bacterial chromosome and replicates independently of the chromosome.

Vertical Gene Flow

The transfer of genetic material (the entire chromosome) from a parent cell to offspring via binary fission or asexual reproduction.

Transformation

A mechanism of horizontal gene transfer involving the bacterial uptake of "free" DNA fragments following the lysis of another bacterial cell.

Conjugation

A mechanism of horizontal gene flow that requires direct cell-to-cell contact between a donor cell and a recipient cell to transfer a plasmid.

F Plasmid

A conjugative plasmid that carries fertility factors providing an increased chance of cell survival and growth in particular environments.

R Plasmid

A conjugative plasmid that contains resistance determinants (R factors) encoding protection against specific antibiotics.

Origin of Transfer (OriT)

The specific base pair sequence on a plasmid where transfer begins by initiating the nick and transfer of one single DNA strand to a recipient cell.

Transfer Genes (TraJ)

Genes on conjugative plasmids that encode proteins for establishing cell-to-cell contact and building the cytoplasmic bridge for plasmid transfer.

Sex Pilus

A protein structure formed by pilin in Gram-negative donor cells that attaches to recipient cell receptors and retracts to bring cells together.

F+ Cell

A donor bacterial cell that contains an F plasmid.

F- Cell

A recipient bacterial cell that lacks an F plasmid.

Pheromone-Induced Conjugation

The Gram-positive conjugation process where recipient cells secrete oligopeptide sex pheromones (e.g., cCF10) to prompt donor cells to produce aggregation proteins.

Episome

A plasmid that is integrated into the host bacterial chromosome.

Hfr Cell

A High Frequency of Recombination donor cell in which the F plasmid has integrated into the bacterial chromosome.