Lecture 8-9 (Motility/Chemotaxis/Growth&Extremophiles)

Question 1

Which mode of bacterial motility would you expect to have on a dry surface?
A. Run-and-tumble
B. Twitching
C. Floating
D. Swimming

Answer 1

B.

Question 2

On a bacterium with a amphitrichous flagellar organization, you would expect a flagellum on both poles of the bacterium, however, on lophotrichous arrangement you would expect multiple flagella at one pole.
T/F

Answer 2

True

Question 3

What would be the analogous structure of MotB be in a sodium (Na+) dependent bacterial flagellum?
A. NQR
B. CheA
C. FliG
D. PomB

Answer 3

D.

Question 4

Which of the flagellar components controls the direction of rotation?
A. MotB
B.MotA
C.Switch Complex
D. FliG

Answer 4

C.

Question 5

In bacteria, rotation of the flagellum counter-clockwise (CCW) will result in a tumble.
T/F

Answer 5

False

Question 6

In response to a recent increasing gradient of a chemoattractant, you would initially expect what?
A. A decreased length of run times.
B. A decreased occurrence of tumbles.
C. A decreased occurrence of runs.
D. A reversion to only smooth swimming runs.

Answer 6

B.

Question 7

In response to being exposed to the same chemoattractant for a while, you would expect what?
A. An increase in tumble frequency.
B. A complete lack of tumbles.
C. No change because it is the same signal.
D. An increase in run duration.

Answer 7

A.

Question 8

If CheY was no longer functional, you would expect what?
A. No flagellum rotation.
B. No effect.
C. The flagellum running CCW.
D. The flagellum running CW.

Answer 8

C. (The flagellar motor is inherently biased towards a counterclockwise rotation.)

Question 9

If CheR was no longer functional, what would you expect?
A. CheY is not phosphorylated
B. CheA constantly phosphorylates CheY
C. CW flagellar rotation
D. MCP methylation.

Answer 9

D.

Question 10

MCP methylation is important for the chemotaxis system’s what?
A. Excitation
B. Adaption
C. Initiation
D. Stopping motility

Answer 10

B.

Question 11

What is the consequence if CheA is mutated (nonfunctioning)?
A. CheY doesn’t get Phosphorylated, therefore Flagellum is stuck going CCW
B. MCP is constantly OFF, therefore, Flagellum is stuck going CW
C. CheY stays phosphorylated, therefore Flagellum is stuck going CW.
CheY doesn’t get Phosphorylated, therefore Flagellum is stuck going CW

Answer 11

A.

Question 12

What is the Flagellar rotation when CheB is mutated (Nonfunctioning)?

Answer 12

Always CW (Tumbling)

Question 13

What is the Flagellar rotation and the consequence when MCP is mutated (Nonfunctioning)?

Answer 13

A. CheA is always “ON” and the the rotation is Always going CW (Tumbling)

Question 14

Why is Flagellum stuck going CCW if the CheY is mutated?
(Hint: what is the consequence if CheY is mutated?)

Answer 14

CheA is unable to phosphorylate it. Nothing binds to the Flagellar motor complex.

Question 15

Bacterial cells go through a process called meiosis, which results in 2 daughter cells.
T/F

Answer 15

False

Question 16

A mutation (loss of function) in minD would also result in a loss of function of what?
A. MinE
B. FtsZ
C. MinC
D. Noc

Answer 16

C.

Question 17

For a pre-existing culture of a bacterial species, what measurement method would require more culturing (growth)?
A. Viable counting
B. Direct counting
C. Flow cytometry
D. Spectrophotometry

Answer 17

A.

Question 18

In a batch culture, you would expect optical density to be increasing when measured with a spectrophotometer in what phase?
A. death phase
B. lag phase
C. log phase
D. Stationary phase

Answer 18

C.

Question 19

For a hyperthermophile, at what temperature would you expect its proteins to function properly at?
A. 21 degrees C (room temperature)
B. 4 degrees C
C. 37 degrees C
D. 80 degrees C

Answer 19

D.

Question 20

A 1.____________
organism would be one that would synthesize everything from basic precursors, while a 2.____________
would require many specific compounds to grow.
Drop down box options:
Nonculturable
Fastidious
Prototrophic
Extremphile

Answer 20

1. Prototrophic
2. Fastidious

Question 21

If FtsZ stopped functioning in a bacterial cell, the cell would eventually die.
T/F

Answer 21

True

Question 22

Which phase is the growth rate greater than the death rate?
A. lag phase
B. log phase
C. Stationary phase
D. Death phase

Answer 22

B.

Question 23

which phase has little to no growth or death?
A. lag phase
B. log phase
C. Stationary phase
D. Death phase

Answer 23

A.

Question 24

If fresh nutrients are aded to a system continuously, what phase will it never enter?

Answer 24

Stationary phase

Question 25

How does superoxide (Free radical) damage macromolecules usually?

Answer 25

It targets DNA and cuts them, damaging the DNA. Extremely lethal.

Question 26

What enzyme detoxifies oxygen free radicals?
A. Catalsae (KatF)
B. Hydrolase
C. Superoxide dismutase (SodA)
D. Isomerase

Answer 26

C.

Question 27

What enzyme converts hydrogen peroxide to water?
A. Catalsae (KatF)
B. Hydrolase
C. Superoxide dismutase (SodA)
D. Isomerase

Answer 27

A.

Question 28

What is the consequence if minC & minD & noc were mutated (Non functioning)?

Answer 28

FtsZ rings would form all over, and chromosome is unprotected, therefore Cells would die.

Question 29

What is the consequence if minE is mutated (Nonfunctioning)?

Answer 29

minC & minD would be in the middle of the cell. Therefore, FtsZ can’t find the middle to Cleave it in half. Would result in Long cells that would eventually die.

Question 30

If either minE or Ftsz were mutated (Nonfunctioning) they would result in the same outcome for the cell.
T/F

Answer 30

True