Unit 1: Lecture 5: Bacterial Flagella

_____________________ and ____________________ also allows some spirochetes to enter and exit blood vessels in order to disseminate in the body.

*Motility* and *Chemotaxis*

______________________ and ____________________may enable some bacteria to swim through mucus in order to make contact with host cells.

*Motility* and *Chemotaxis*

__________________ enable the spirochetes to penetrate tissues as well as enter the lymphatics and bloodstream enabling their dissemination to other body sites.

*Motility, Chemotaxis,* and *Invasins*

Humans are the ONLY *natural host*.

*Treponema pallidium*

Typically transmitted *sexually* by contact with infected lesions; may be transmitted congenitally.

*Treponema pallidium*

________________ _________________ is a spirochete 0.1 µm X 5-15 µm.

*Treponema pallidium*

A *Bacterial flagellum* consists of:

1. A *filament* 2. A *hook* 3. A *basal body*

A single flagellum at *both ends* of the organism.

Amphitrichous

Internal flagella found *only in the spirochetes.*

Axial filaments

Most bacteria with *polar flagella*, can rotate their flagella:

BOTH *Clockwise* and *Counterclockwise*.

In bacteria with *polar flagella*: When it rotates *clockwise*, it pulls the bacterium _____________________.

Backward

The ____________________ ___________________ consists of a *filament* that extends from the cell surface, a *basal body* that anchors the filament to the bacterium and functions as a *molecular motor*, and a *flexible hook* that couples the filament to the basal body.

Bacterial flagellum

The ______________ _____________ consists of a rod and a series of rings that anchor the flagellum to the cell wall and the cytoplasmic membrane.

Basal body

The _____________________ is the rigid, helical structure that extends from the cell surface.

Filament

The __________________ of bacterial flagella is a *PAMP* that binds to *PRRs* on defense cells to *initiate innate immunity.*

Flagellin

In bacteria with *polar flagella*: If the flagellum is rotating *counterclockwise*, it pushes the bacterium ________________.

Forward

The ____________ is a flexible coupling between the filament and the basal body

Hook

*Two or more* flagella at *one or both* poles.

Lophotrichous

A single flagellum, usually at *one pole*.

Monotrichous

Flagella over the *entire surface*

Peritrichous

*Energy* for *rotation* comes from the:

Proton motive force

In bacteria with *polar flagella*: These bacteria change *direction* by changing the:

Rotation of their flagella

What is the infection *Treponema pallidium* causes?

Syphilis

A motile response to an environmental stimulus.

Taxis

If a bacterium has a peritrichous arrangement of flagella, ________________ of the flagella causes them to form a single bundle that propels the bacterium in long, straight or curved runs without a change in direction.

counterclockwise

*Internal flagella*, or *axial filaments*, are seen only in:

spirochetes

The overall function of bacterial flagella is:

to keep bacteria in an optimum environment via taxis.