Plasmid Biology and Genetic Transfer Methods

These flashcards cover key vocabulary and concepts related to plasmid biology, genetic transfer methods, and the mechanisms of antibiotic resistance in bacteria.

Plasmid

A genetic structure in a cell that can replicate independently of the chromosomes.

Theta replication

A mechanism of plasmid replication resembling the replication of circular DNA, arising from a double-stranded DNA molecule.

Rolling Circle Replication

A method of plasmid replication that results in the linear formation of a single-stranded DNA that can produce multiple circular DNA copies.

Post-Segregational Killing

A mechanism to ensure low-copy-number plasmids are retained in daughter cells, mediated by addiction modules.

Addiction Modules

Gene cassettes in plasmids that encode a toxin and an antidote, where the antidote has a shorter half-life than the toxin.

CcdB toxin

A protein that poisons DNA gyrase, influencing the supercoiling of DNA and has a long half-life.

Hfr strain

A bacterial strain in which a conjugative plasmid has integrated into the chromosome, leading to a high frequency of recombination during conjugation.

Conjugative plasmids

Plasmids capable of promoting their own transfer from one bacterial cell to another through physical contact.

Competence

The ability of a cell to take up free DNA from its environment.

Quorum Sensing

A process by which bacteria communicate based on cell density using signaling molecules to coordinate certain behaviors.

Generalized transduction

A process in which any bacterial chromosomal fragment can be transferred from one bacterium to another via phages.

Specialized transduction

The transfer of specific bacterial genes adjacent to a prophage insertion site into another bacterium.

Type III Secretion System (T3SS)

A needle-like structure used by some bacteria to inject proteins directly into host cells, facilitating interactions such as symbiosis or pathogenicity.

Integrons

Mobile genetic elements that can capture, rearrange, and express gene cassettes, particularly associated with antibiotic resistance.

Bacteriorhodopsin

A protein used by halophilic archaea to capture light energy for ATP generation.

Methanogenesis

A biological process where methanogenic archaea produce methane as a metabolic byproduct under anaerobic conditions.

R plasmids

A type of plasmid that carries genes for antibiotic resistance and can be transferred between bacteria.