Exam 3 Lecture 20

Question 1

If bacteria can’t swim what are they often defective at?

Answer 1

The ability to cause infections

Question 2

If bacteria can’t tell where they are going what else might they not be able to do?

Answer 2

Cause infections.

Question 3

What are the simplest nervous systems we know?

Answer 3

Bacterial nervous systems

Question 4

What are the 4 types of motility?

Answer 4

Swimming in liquid (flagella)

Swarming on surfaces (flagella)

Twitching on surfaces (pili)

Gliding on Surfaces (mechanism not totally understood)

Question 5

Possible mechanisms of gliding?

Answer 5

slime extrusion, pili plus slime, counter-movement of the outer membrane (like a tank track)

Question 6

Describe peritrichous movement.

Answer 6

Multiple flagella, CCW rotaion = bundle flagella and forward movement

CW rotation = Flagella pushed apart and a Tumble

Then CCW rotation and forward movement again

Question 7

Speed of peritrichous movement?

Answer 7

35 µm/second or 18 body lengths/second

Question 8

Describe the two types of polar flagella movement?

Answer 8

Reversible- CCW rotation= forward or CW rotation= backward or reverse

Unidirectional- CW rotation = forward, stop and reorient then CW rotation = forward

Question 9

Speed of polar flagella movement?

Answer 9

80 µm/second or 40 body lengths/sec

Question 10

Ways to measure chemotaxis?

Answer 10

Test tube with attractant or repellant in a beaker of bacteria and measure the cells per tube over time

Agar plate and measure distance they move

Microscopy and computers

Question 11

What is a biased random walk like with no attractant?

Answer 11

CCW runs are shorter

Question 12

What are biased random walk runs like when an attractant is present?

Answer 12

They are longer

Question 13

How long does bacterial “memory “last?

Answer 13

1 min max, very short

Question 14

Common two-part signal transduction system?

Answer 14

1. A histidine kinase receptor that receives the signal and gets phosphorylated
2. Response regulator that is phosphorylated by the histidine kinase

Question 15

Fill in the blanks

1. ___ is a ___ that receives a _____signal.
2. It attaches to ____ which is an adaptor that attaches to ____ a histidine kinase that is phosphorylated in response to the signal received.
3. ___ passes a phosphate each to ___ and ___.
4. ___when phosphorylated binds to the___ which (does what)___ in milliseconds.
5. ___ takes off a ___ from the ___ to turn off in 5 secs.
6. To reset the system and change the flagella spin back to CCW, ___despohsporylates___ and ___ adds a methyl group back on ___.

Answer 15

1. MCP (methyl-accepting chemotaxis protein), transmembrane protein, repellant
2. CheW, CheA
3. CheA, CheB, CheY
4. CheY, Flagella motor, causes it to change direction and make bacteria tumble
5. CheB, CH3, MCP
6. CheZ, CheY, CheR, the MCP

Question 16

Two types of energy taxis?

Answer 16

Aero- toward oxygen

Photo- toward light (usually certain wavelengths)

Question 17

Mechanism used in swarming motion?

Answer 17

Polar flagella

Question 18

Name 3 functions of pili?

Answer 18

1. Sex pili
2. Attachment (fimbrae)
3. Twitching- Type IV pili mediated twitching)

Question 19

Can a bacteria have pili and flagella at the same time?

Answer 19

Yes

Question 20

Name a bacteria type that often glide?

Answer 20

Myxobacteria (slimes)

Also C. hutchinsonii, a gram-negative bacterium that belongs to the phylum Bacteroidetes

Question 21

How is gliding activity is thought to work (latest model) in Flavobacterium/Cytophaga groups?

Answer 21

The inner membrane has motors in it causing the outer membrane to move to the right rolling over the inner membrane causing the cell to move to the left