Taxis

Question 1

Mechanism of flagellum movement

Answer 1

Screw propeller
Proton gradient channels and trans-membrane proton gradient
proton motive force-> mechanical energy

Question 2

Taxis

Answer 2

Innate behavioural response by an organsim to a stimulus
Orientated movement of freely motile organsims towards attractants and away from repellents

Question 3

+ taxis

Answer 3

Towards stimulus

Question 4

• taxis

Answer 4

away from stimulus

Question 5

Movement determination

Answer 5

direction of flagella rotation
CCW is forward
CW is tumble

Question 6

Absence of chemical gradient

Answer 6

run and tumble normally

Question 7

Exposed to attractant gradient

Answer 7

Longer runsand shorter tumbles

Question 8

Exposed to repellent gradient

Answer 8

Shorter runs towards
longer tumbles
longr runs away

Question 9

Temporal sensing mechanism

Answer 9

B have memory where they can tell concentration of location B is different from A

Question 10

Prove temporal sensing

Answer 10

Take nonstimulated B and mix with liquid rich in attractant and this causes very long runs even though there is no immediate change in gradient

Question 11

Movement with many flagellum

Answer 11

CW causes flagella to spread out
CCW causes flagella to bundle and push in specific direction
Recieving a stimulus and inducing a response is very fast

Question 12

Phototaxis

Answer 12

Oriented movement of motile organism in response to light stimulus

Question 13

Scotophobotaxis

Answer 13

Fear of darkness
-When illuminated under microscope and go into darkness, they immediately turn around
-Not light graident of intensity only presence or absence triggers this

Question 14

Phototactic response

Answer 14

Movement is based off light intensity
evolved to avoid high intensity because it damages them

Question 15

Magnetotaxis

Answer 15

Motility directed by a magnetic field not in response to field

Question 16

Magnetotactic B

Answer 16

Mostly aquatic B
Orient and migrate along magnetic field lines
Earth’s magnetic fields are a navigational device
-Magnetospirillum

Question 17

Is magnetotaxis a tactic response

Answer 17

No. It doesnt respond to magnetic field but uses it to move towards or away from other gradients
-Movement is more efficient as it is in 2D instead of 3DD and is used to find O2

Question 18

Inclusion bodies of magnetotaxis

Answer 18

Magnetosomes
Fe3O4 (magnetite)
Fe3S4 (greigite)

Question 19

M with eye

Answer 19

Synechocystis sp PCC 6803

Question 20

Synechocystis sp

Answer 20

-Spherical microlens
Directly and accurately sense the position of light source:
*Not just respond to spatiotemporal light gradient
*See the light source as high resolution image
Movement toards light is not run-and-tumble but twitching/gliding motility using type IV pili (T4P)