Topic 2-L7 - Movement of bacterial cells

Question 1

Motility:

Answer 1

The ability to propel your own movement

Question 2

Example of bacteria that isn’t motile

Answer 2

Yersinia pestis.

Question 3

Flagellum is a

Answer 3

large, complex, multi-protein machine that powers bacterial movement

Question 4

Flagellum includes a

Answer 4

long, thin filament that acts like a propeller. It is rotated using a motor that is anchored in the cell envelope.

Question 5

Rotation of flagellum propels cell, enabling the cell to

Answer 5

“Swim” and “swarm”

Question 6

Flagella can be built at different

Answer 6

positions along the cell – different bacteria have different numbers/arrangements

Question 7

5 types of different flagella types of cells

Answer 7

A) Peritrichous (many across pole/body)
B) Monotrichous or Polar (single – at pole)

C) Lophotrichous (many, all at one pole)

Not shown – amphitrichous – (both poles) Not shown – atrichous (no flagella at all)

Question 8

Flagella rotate in both directions?

Answer 8

YES

Question 9

Longer “runs” –

Answer 9

Counterclockwise rotation, helical bundle formed at tail of cell - cell moves forward

Question 10

Short “tumbles” –

Answer 10

one or more flagella rotate clockwise – bundle falls apart – bacteria tumbles, assumes new, random orientation

Question 11

Bacteria with a reversible flagellum, rotation in

Answer 11

opposite directions reverses direction of movement

Question 12

unidirectional flagella –

Answer 12

rotation stops/starts. Random movement during “stops” change direction of bacterium

Question 13

3 segments of the flagellum:

Answer 13

1) filament
2) hook
3) basal body

Question 14

Filament

Answer 14

(long, thin propeller – drives movement)

Question 15

Hook

Answer 15

(adaptor that connects filament to

the basal body)

Question 16

Basal body.

Answer 16

Core of the structure. Powers rotation of filaments

Question 17

Flagella motor function

Answer 17

Harnesses proton motive force to drive rotation

Question 18

The Central rod in the flagella motor passes through a series of rings:

Answer 18

MS ring (cytoplasmic membrane)
C ring (cytoplasm) 
P ring (peptidoglycan) 
L ring (outer membrane)

Question 19

Stator in the flagellar motor couples the

Answer 19

flow of protons to rotation of the MS ring – behaves like a “proton turbine”

Question 20

MS ring

Answer 20

rotates rod…and ultimately

hook and filament.

Question 21

L/P rings act like

Answer 21

bearings (or bushings) to help rotation

Question 22

C ring important for:

Answer 22

generating torque, switching motor direction, flagellin secretion

Question 23

Gram Positive Flagellum lacks

Answer 23

P/L rings

– only contains C/MS rings

Question 24

The long filament that drives movement in the flagellum is made of thousands of copies of a single protein called

Answer 24

flagellin

Question 25

flagellin

Answer 25

Filament is rigid, helical and hollow

• Free at one end (out in environment) –
  connected to motor (via rod, hook) at
  other end
• Highly conserved in bacteria

Question 26

Synthesis of the flagellum

Answer 26

Made form inside out

Question 27

Flagellin is produced in

Answer 27

cytoplasm

Question 28

Flagellin is

Answer 28

secreted via the “export apparatus” through a thin pore in the basal body/hollow filament - assembles filament with help of cap proteins

Question 29

The sport of flagellin through

Answer 29

“Type III secretion system”

Question 30

“Type III secretion system”

Answer 30

a related system is used as a protein toxin injection system by certain
bacterial pathogens

Question 31

Spirochetes have a flagellum (“axial filament”) that resides in periplasm –

Answer 31

rotation results in corkscrew motion of entire bacterium

Question 32

Flagellar motility if often highly regulated –

Answer 32

even motile bacteria can adopt atrichous/non-motile state

Question 33

Taxis is the

Answer 33

directed movement of bacteria. Accomplished using a “bias random walk”

Question 34

Chemotaxis:

Answer 34

Movement in the direction of gradients of increasing or decreasing concentration to particular chemical(s) (via chemoreceptors)

Question 35

If bacterium moving toward desirable nutrient, tumbles inhibited –

Answer 35

longer runs.

Question 36

If bacterium moving away from desirable nutrient, tumbles inhibited –

Answer 36

More frequent tumbles

Question 37

Phototaxis:

Answer 37

Movement toward/away from light

Question 38

Aerotaxis:

Answer 38

Directed motility in response to O2

Question 39

twitching motility

Answer 39

Non-flagellar movement

Question 40

twitching motility, in which a

Answer 40

Type IV pilus attaches to a surface and then retracts

-Sort of like a grappling hook