2-6: Movement of Bacterial Cells Flashcards

1
Q

What is motility

A

The ability to propel your own movement

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2
Q

Give an example of a non-motile bacteria

A

Yersinia pestis, a bacterial pathogen

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3
Q

What is the flagellum

A

Large, complex, multi-protein (~50) machine that powers movement

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4
Q

Describe the general structure of a flagellum

A

Long, thin filament that acts as propeller, rotated by motor anchored in cell envelope

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5
Q

What is swarming

A

Coordinated multicellular movement across a solid surface

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6
Q

What are the different flagellar arrangements

A

Peritrichous = many across body/pole
Monotrichous = single at pole
Lophotrichous = many, all at one pole
Amphitrichous = both poles
Atrichous = none

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7
Q

“runs” in peritrichous bacteria

A

Counterclockwise, flagella bundle at tail, cell moves forward

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8
Q

Descibe flagellar rotation of short “tumbles” in peritrichous bacteria

A

One or more flagella rotate clockwise, therefore bundle falls apart, tumbles, assumes new random orientation

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9
Q

What two ways do monotrichous bacteria move

A

Reversible and unidirectional flagella

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10
Q

How do monotrichous bacteria with unidirectional flagella move?

A

rotation stops/starts, movement during stops = direction change

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11
Q

How do monotrichous bacteria with reversible flagella move

A

Can rotate clockwise or CCW, rotation in the opposite direction will reverse the movement

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12
Q

What are the three segments of the flagella

A

1) Filament (long, thin propeller driving movement)
2) Hook (adaptor that connects filament to basal body)
3) Basal body (core of structure, powers rotation, motor is part of)

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13
Q

What drives rotation of the flagellar motor

A

Proton motive force

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14
Q

What are the parts of the gram negative flagellar motor

A

Central rod, MS ring, C ring, P ring, L ring, stator

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15
Q

Where are the MS, C, P and L ring located

A

MS = CM
C = cytoplasm
P = peptidoglycan
L = OM

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16
Q

What does the stator do

A

couples flow of protons to rotation of MS ring - acts like a turbine

17
Q

What does the MS ring do

A

Rotates rod, ultimately the hook and filament

18
Q

What do the L/P rings do

A

Bearings to help rotation

19
Q

What does the C ring do

A

Generate torque, switch motor direction, flagellin secretion

20
Q

What does gram positive flagellum lack

21
Q

What is flagellin

A

Proteins, thousands of which make up the filament

22
Q

How long and wide is the filament

A

5-10um long, 20nm wide

23
Q

Describe the structure of the filament

A

Rigid, helical, and hollow

24
Q

Is the filament highly conserved in bactiera?

25
How is flagellin detected by our immune systems
It is an important antigen (H antigen)
26
How is flagellum made
Built inside -> out Produced in cytoplasm, secreted via the hollow filament. New subunits will assemble at the end (outside the cell) with the cap proteins
27
What secretion system is used to export flagellin?
Type III secretion system. A related system is used as a protein toxin injection system by certain pathogens
28
Variations in some bacteria flagellar motility?
Some use Na+ gradient, spirochetes have axial filament that resides in periplasm resulting in corkscrew motion
29
What is a taxis
Directed movement of bacteria using bias random walk
30
what is chemotaxis
Movement in direction of gradients (increase or decrease) in concentration of a chemical which is detected by chemoreceptors
31
How does tumble frequency change with moving TOWARDS a stimulus?
Tumbles inhibited, longer runs
32
What is phototaxis?
P = movement towards/away from light
33
What is aerotaxis?
directed motility in response to O2
34
What is twitching motility
Non-flagellar motility, uses a type 4 pilus attaches to surface then retracts like a "grappling hook"