Pili and Flagella

Question 1

Explain the 3 Bacteria appendages and what their functions are

Answer 1

1) flagella: locomotion
2) Pili and fimbriae: adhesion
3) Sex pili: Transfer of DNA

Question 2

Pili are widespread in what classification of bacteria?

Answer 2

Pili is widespread in GRAM NEGATIVE and rare in positiev

Question 3

True or False, pili are normally Peritrichous along the cell

Answer 3

True (all over the cell surface)

Question 4

Explain Pili’s structure and mobility

Answer 4

Pili are straight rods unlike flagella (helical)
Pili cant move/rotate unlike flagella
Pili have a simple base unlike flagella which have a complex base

Question 5

what is the only type of pili that is used for a little bit of motility in pathogenesis?

Answer 5

Type 4 (IV) pili creates a twitching motility which is surface mediated. It is NOT swimming

Question 6

What is UPEC?

Answer 6

An E. Coli that has specialized Pili that cause urinary tract infections

Question 7

E. Coli Pap Pili: explain Pap G

Answer 7

G is the actual adhesion at very tip of the pili on the pili fibre

Question 8

E. Coli Pap Pili: explain Pap F

Answer 8

F is the adhesion adapter that connects the G adhesion to the pili fibre

Question 9

E. Coli Pap Pili: explain Pap E

Answer 9

E is the major component of the pili fibre

Question 10

E. Coli Pap Pili: explain Pap K

Answer 10

K is the adapter that connects the pili fibre (mainly E) to the main pilus structure

Question 11

E. Coli Pap Pili: explain Pap A

Answer 11

Pap A is the bulk of the pilus rod

Question 12

E. Coli Pap Pili: explain Pap H

Answer 12

anchors the rod (A) to the cell

Question 13

E. Coli Pap Pili: explain Pap D

Answer 13

Pap D is a chaperone protein inside the periplasmic space

Question 14

E. Coli Pap Pili: explain Pap C

Answer 14

Pap C is located in the outer membrane and it removes incoming proteins from chaperone Pap D

Question 15

Explain G-FEKAH’ CD

Answer 15

This is the the order of the PAP regions from furthest from the cell to the periplasm.

Question 16

Explain Pili synthesis up until Pap C (4 points)

Answer 16

• translated Pap subunits are normally made as precursor with a signal peptide
• signal peptides tell cell it needs to be exported
• as the cell is exported out of the PM, the signal peptide is cut off
• Pap D binds the subunit in the periplasm and delivers it to Pap C in the outer membrane

Question 17

what occurs if Pap D becomes mutated?

Answer 17

No pilus will form and subunits will degrade in periplasm!!

Question 18

Explain the second half of Pili synthesis (3 points)

Answer 18

• Pap C creates a donut like spore that feeds the pilus out of the OM
• Assembly starts with furthest out proteins therefore Pap G is the first subunit
• Major shaft proteins come in (Pap A) until one pap H comes which terminates the pilus

Question 19

how many Pap H does it take to stop pilus growth?

Answer 19

one. On avg pilus have 1000 pap A’s

Question 20

Explain the gene organization of the pilus. How does A get produced so much more than the other subunits

Answer 20

• there is a transcriptional terminator after the A gene that causes RNA polymerase to fall off.
• small amounts of it pass this and transcript the rest of the genes

Question 21

what is the force that allows flagella to rotate?

Answer 21

Proton motive force!!

NO ATP IS USED

Question 22

Explain Monotrichous

Answer 22

Only one flagellum

Question 23

Polar flagellum ?

Answer 23

there is a flagellum at end of the cell

Question 24

Amphitrichous?

Answer 24

there is flagella at both ends of the cell

Bi - polar

Question 25

Lophotrichous?

Answer 25

Cluster of flagella at one or both ends of the cell

Question 26

Peritrichous?

Answer 26

spread every where

Question 27

What are the three main components of flagella?

Answer 27

Filament, the hook, and the basal body

Question 28

What is the major difference between gram negative and gram positive bacteria flagellum?

Answer 28

Negative: basal body is complex with 4 rings positive: basal body is simple with 2 rings (S and M)

Question 29

explain the filament structure of flagellum

Answer 29

10,000's of copies of flagellin | Is capped by Hook Associated protein 2 (HAP2)

Question 30

explain Flagellin properties

Answer 30

- is deficient in cysteine, and tryptophan | - will dissociate in presence of acid or heat

Question 31

What is HAP2?

Answer 31

Hook Associated Protein 2 which caps the Filament structure

Question 32

explain the hook region of flagella

Answer 32

- composed of hook proteins - has a defined length of 80nm - HAP1 and HAP3 are at junction between filament and hook

Question 33

Explain the Basal Body structure in Gram Negative bacteria. Name rings

Answer 33

- composed of a rod and 4 rings - L, P, S, and M are 4 rings - gram positive only have S and M

Question 34

Explain the L ring

Answer 34

In the plane of LPS (outer membrane) | LPS = lipopolysaccharide

Question 35

Explain the P ring

Answer 35

In the plane of the peptidoglycan layer

Question 36

Explain the S ring

Answer 36

Supramembraneous, just above PM

Question 37

Explain the M ring

Answer 37

M ring is in plane with PM

Question 38

Explain how flagella rotates

Answer 38

- There are 3 switch proteins - FliN, FliG, and FliM - Mot A and Mot B are stators which ensure the flagella is stably connected to the PM - they also form proton gradient for force

Question 39

how do basal body rings get exported?

Answer 39

they have signal peptides

Question 40

how do HAPS, flagellin, and hook get exported?

Answer 40

they travel up the interior of the growing filament

Question 41

Why is HAP2 important

Answer 41

It caps the filament and therefore ensures when the flagella grows that the subunits do not diffuse away.

Question 42

Explain gene organization of flagella

Answer 42

unlike pili which have one operon controlling the whole structure, E. coli flagella have over 40 genes involved in 10 operons neither flagella or pili gene control is "Wasteful"

Question 43

explain the order of transcriptional control?

Answer 43

- input from many signals give the cell an idea of the environment - then early genes are activated - then middle genes - then late genes

Question 44

explain early genes

Answer 44

Early genes have master control | they are transcriptional activators

Question 45

explain middle genes

Answer 45

- Middle genes will only transcribe if activated by early genes - These genes code for basal body formation and hook transportation

Question 46

Late genes?

Answer 46

must be activated by middle genes | codes for flagella filament

Question 47

Besides flagella rotation what other types of motility are possible? explain both

Answer 47

1) twitching motility done by type IV pili - they crawl by extending and shortening pili 2) gliding motility - expels slime which glides bacteria forwards

Question 48

explain myxobacteria

Answer 48

A form of bacteria that has both type IV pili and slime for ultra motility

Question 49

What is the only microbe to have ATP driven legs for motility

Answer 49

mycoplasma mobile