Lecture 1B: Cell Locomotion (Archaella, gliding motility and Taxis

Question 1

• even thinner than the flagellum.
• about half the diameter of the bacterial flagellum (around 10-13 nm).

Answer 1

Archaella

Question 2

Movement of archaella

Answer 2

By rotation

Question 3

Have a very ______ ________ to the bacterial flagellum.

Answer 3

little homology

Question 4

To what structure does the Archaellum similar?

Answer 4

type IV pilus

Question 5

Common cell wall of the Archaea

Answer 5

S-layer

Question 6

Instead of L, P, MS, and C ring, what structure (?) stabilizes the filament of the archaea?

Answer 6

FlaJ

Question 7

Protective and Adaptive mechanism of Bacteria

Answer 7

Gliding motility

Question 8

Does archaea exhibits gliding motility?

Answer 8

No. Bacteria can only exhibit gliding motility.

Question 9

Gliding motility is _______ and ________ than swimming.

Answer 9

slower and smoother

Question 10

Why does the movement of gliding motility occurs away from colony?

Answer 10

to avoid the crowd.

Question 11

Gliding requires _______ ________ (semi-solid or solid) but there has to be moisture.

Answer 11

surface contact

Question 12

Mechanisms of gliding motility

Answer 12

-Excretion of polysaccharide slime.
-Structure is similar to type IV pili
-Movement is twitching motility
-Gliding specific proteins involve in adhesion complexes and other specialized proteins.

Question 13

On the outer membrane you can find proteins interspersed in the membrane that serve as _________ ________.

Answer 13

Gliding proteins

Question 14

Where does the gliding proteins connected?

Answer 14

to the transmembrane proteins in cytoplasmic membrane.

Question 15

The movement of outer membrane glide proteins moves _________ to the movement of the cell.

Answer 15

oppositely

Question 16

The opposite movement of glide proteins to the movement of cell creates _________ that kind of pushes the cell in opposite direction.

Answer 16

friction

Question 17

Directed movement in response to chemical or physical gradients.

Answer 17

Taxis

Question 18

Response to chemicals

Answer 18

Chemotaxis

Question 19

Response to light

Answer 19

Phototaxis

Question 20

Response to oxygen

Answer 20

Aerotaxis

Question 21

Response to ionic strength

Answer 21

Osmotaxis

Question 22

Response to water

Answer 22

Hydrotaxis

Question 23

• Best studied in E.coli.
• “run and tumble’ behavior.
• Move by rotation
• Bacteria respond to temporal difference in chemical concentration
• Monitor/sample environment with (?) that sense attractants and repellants

Answer 23

Chemotaxis

Question 24

Smooth forward motion, and the flagellar motor rotates counterclockwise (right to left)

Answer 24

Run

Question 25

Cell stops and jiggles, flagellar motor rotates clockwise (left to right), flagellar bundle comes apart.

Answer 25

Tumble

Question 26

- Similar but not identical to peritrichous cells. - Many (e.g., Pseudomonas) can fully reverse flagellar rotation, avoid tumbling and reversing direction. - Some (e.g., Rhodobacter) stop and are affected by Brownian motion.

Answer 26

Chemotaxis in peritrichous flagellated bacterium

Question 27

Allows phototrophic organisms to optimize position for light harvest.

Answer 27

Phototaxis using Photoreceptors

Question 28

Entering darkness causes cell to tumble, reverse direction, head back to light.

Answer 28

Scotophobotaxis