Structure - Bacterial Movement

Question 1

What are the three structures of

Answer 1

Basal Body
Hook
Filament

Question 2

What is the function of the Basal Body?

Answer 2

Drives rotary motion of the flagella through the MS-ring

Question 3

MS-Ring

Answer 3

A transmembrane complex acting as the core of the flagellar motor and template for flagellar assembly.

Question 4

What is the function of MS-Ring?

Answer 4

Forms a membrane pore to allow ionic flow for rotary motion generation.

Question 5

What is the function of FliG?

Answer 5

Interacts with flagellar motor proteins to regulat direction of flagellar motion.

Question 6

What are the three rings of he flagellar?

Answer 6

MS-Ring
L-Ring
P-Ring

Question 7

What is the Hook composed of?

Answer 7

FlgE protein

Question 8

What is the structure of the FlgE protein?

Answer 8

Banana-like conformation with an NTD anchoring to the basal body and CTD binding hook and filament.

Question 9

What is FlgE important for?

Answer 9

Mobility regulation, with length and shape able to be controlled

Question 10

What is the filament composed on?

Answer 10

Flagellin proteins in a helical arrangement

Question 11

What is the function of the filament?

Answer 11

Propelling bacteria throguh mediums.

Question 12

What is the 3D structure of the flagellin?

Answer 12

11 protofilaments winding around each other, each composed of several flagelling

Question 13

What is the primary motor ring?

Answer 13

C-Ring composed of FliG protein

Question 14

How is movement driven in the C-Ring?

Answer 14

FliM and FliN rotate when ions flow through the motor.

Question 15

What is the importance of the Proton Motive Force in rotation?

Answer 15

ETC pump ions creating an electrocemical gradient either side of the membrane, where the motor reverts this flow to generate force rotating the C-RINg

Question 16

What does the Proton Motive Force do for torque generation?

Answer 16

Creates and electrical potential and pH higher outside the membrane driving protons back into the cell.

Question 17

What drives proton flow across the membrane?

Answer 17

Stator complex of MotA and MotB with interaction with C-ring charged residues causing either CW or CCW

Question 18

FliM

Answer 18

This stabilises charged residues in FliG to organise rotation

Question 19

FliN

Answer 19

This stabilises FliM and FliG interactions forming a hexameric ring in the centre of the C-Ring

Question 20

How is torque generated by the stator?

Answer 20

Release of stored energy by conformational changes or generation of electric field interaction with stator complex.

Question 21

Run

Answer 21

Linear motion by chemotaxis reocngition of environmental attractants or repllants

Question 22

Tumbles

Answer 22

Rapid switches in directions of rotation changing thus orientiation and direction of movement

Question 23

Chemoreceptors

Answer 23

These detect concentration gradients in the environment and through signally pathways relay this to the motor.

Question 24

CheY

Answer 24

This is an enzyme catalysing phosphoryl group transfer from phosphohistidine in CheA to its own aspartate residues inducing CC allowing CheA binding to flagellar motor.

Question 25

What happens to CheZ in presence of repellants?

Answer 25

CheZ increases in concentration removing the phosphoryl group from CheY resulting in tumbles.

Question 26

What happens when chemoreceptor binds attractants?

Answer 26

CC triggered and CheA autophosphorylates a hisitinde residues transferring phosphoryl to aspartate on CheY allowing its interaction with flagellar.

Question 27

Polar Flagellation

Answer 27

Flagella attaches at one/both ends of the cell.

Question 28

Lophotrichous

Answer 28

Having multiple flagella at the same point

Question 29

Peritrichous

Answer 29

Flagella inserts at many locations around cell surface

Question 30

Amphitrichous

Answer 30

Flagella is found both poles of the cell.

Question 31

Chemotaxis

Answer 31

The ability of bacteria to move toward a location in response to electrochemical graidents.

Question 32

What does both CCW and CW cause?

Answer 32

CCW causes tumbling and CW causes Run

Question 33

How fast can the flagellar rotate?

Answer 33

300 revs per second and 60 cell lengths per second.