Bacterial Flagella and Motility

Flashcards covering the mechanism of movement, types, ultrastructure, and chemical composition of bacterial flagella based on lecture notes.

Basal body

The motor and anchoring region of flagellum embedded within the bacterial cell envelope consisting of a central rod surrounded by a series of rings.

Proton motive force (PMF)

The energy source, derived from the movement of hydrogen ions across the plasma membrane, that powers the rotary motor of the basal body.

Run

A smooth forward movement produced by the counter clockwise rotation of bacterial flagella.

Tumble

A random change in direction caused by clockwise rotation, which results in flagella separating.

Chemotaxis

The movement of bacteria towards nutrients and away from harmful substances, performed using an alternating sequence of run and tumble.

Monotrichous

A specific type of flagellar arrangement on a bacterial cell.

Amphitrichous

A specific type of flagellar arrangement on a bacterial cell.

Lophotrichous

A specific type of flagellar arrangement on a bacterial cell.

Peritrichous

A specific type of flagellar arrangement on a bacterial cell.

L-ring

A component of the basal body in Gram-negative bacteria that is embedded in the outer membrane (lipopolysaccharide layer).

P-ring

A component of the basal body in Gram-negative bacteria located in the peptidoglycan layer.

MS-ring

A component of the basal body present within the plasma membrane of both Gram-negative and Gram-positive bacteria.

C-ring

A component of the basal body located on the cytoplasmic side of the plasma membrane involved in motor function and switching the direction of rotation.

Flagella

A long, slender, whip-like appendage projecting from the surface of certain bacterial cells primarily responsible for motility.

Taxis

The term used for the directed movement of bacterial cells.

Flagellin

The protein subunits that polymerize to form the long external filament of the bacterial flagella.

Eukaryotic Flagella Composition

Unlike bacterial flagella, these contain microtubules composed of the protein tubulin.

Filament

The longest and most visible part of the flagellum, which is a hollow helical structure that generates thrust during movement.

Hook

A short curved structure connecting the filament to the basal body that acts as a flexible universal joint to transmit rotational force.

Flagellated Bacteria Examples

Species including Esherichia coil, Salmonella typhi, Vibrio species, Proteus species, and Pseudomonas aerugin as.