MCB 2610: Exam 3 pt. 2

flagella are agents of?

locomotion

do all bacteria have flagella? If so, do they express it all the time?

not all have it, if you do you don't express it all the time

flagella are?

spiral, hollow, rigid filaments extending from the cell surface

will you find different kinds of flagella togehter?

no; example you will never find polar flagella with peritrichous flagella

different types of flagella

monotrichous, polar flagellum, amphitrichous, lophotrichous, peritrichous

monotrichous

one flagellum

polar flagellum

flagellum at end of cell

amphitrichous

one single flagellum at each end of cell

lophotrichous

cluster of multiple flagella at one or both ends of cell

peritrichous

flagella spread over entire surface of cell

3 parts of flagella

filament, hook protein and basal body

filament

largest portion that you can see

hook protein

flexible cupular linking filament and basal body

basal body

anchored to PM keeping entire flagellum anchored to bacteria, most complex portion and structure differs between gram +/-

difference in basal body in gram + vs. gram -

gram + has its 2nd ring associated with peptidoglycan and inner ring in PM

where do you find the motor to turn flagella?

in basal body

P-ring in gram - is embedded in?

peptidoglycan layer

L-ring in gram - is located in?

outer membrane

filament in flagella is?

hollow

hook is more narrow or wider than filament?

wider and is flexible acting as link between filament and basal body

what is needed to make our entire flagella genes organized into operon?

20-30 diff. genes and their associated proteins

operon allows us to?

transcribe all the genes at the same time

self assembly is used to?

organize themselves into a filament

why is the filament hollow?

to shunt things up to the tip

the n-cap gets placed on top of?

the flagellin

flagella is related to what type of secretion system?

type 3 - move things all the way across

flagellum rotates like a propeller and there is very rapid rotation up to?

1100 revoltions/sec

counterclockwise rotation causes what kind of motion

forward straight line movement

clockwise rotation disrupts run causing cell to?

stop and tumble to change direction

what can we use flagella for?

taxis and non-directed motion

taxis what is it and what are the two types?

directed movement towards or away from something; chemo and photo

chemotaxis - in order to have it what must you have?

chemoreceptors and flagella

chemotaxis is movement?

towards a chemical attractant or away from a chemical repellent

changing concentrations of chemical attractants causes?

chemical repellents to bind to chemoreceptors of chemosensing system

chemotaxis - in the presence of attractants tumbling frequency is?

intermittently reduced and runs in direction of attractant are longer

high concentration of attractant = ?

higher frequency of runs

motility by flagella - by using chemoreceptor proteins to sense changes in concentrations of attractants or repellents, cells can produce?

more runs to move in a particular direction

alternating runs and tumbles result in?

no directed movement

prolonged runs can move a bacterium?

toward or away from a chemical

chemotaxis system default orientation is?

counter-clockwise (run) but can go to clockwise (tumble)

CheW

allows us to transfer info to CheA

CheA

sensor kinase; autophosphorylates under appropriate conditions

CheY

causes molecular switch from CCW to CW

2 chemo component regulatory system involves?

all CheY proteins which take info and give it to flagella

CheY when phosphorylated diffuses to basal body and in this state causes?

flagella to stop CCW rotation and move to CW

if there is a presence of attractant what happens?

prevention of autophosphorylation of CheA to prevent CheY from switching from run to tumble

flagellum is a 2 part motor producing torque - what are the 2 parts?

rotor and stator

rotor - what rings turn and interact with stator?

C (FliG protein) ring and MS (FliF) ring

stator (electromagnet) contains what motor proteins?

Mot A and Mot B

Mot A and Mot B proteins form __ that proton flows down

channel

archaea have a?

push me-pull me alternation with no tumbling

it takes energy to spin flagella what kind of energy do we use?

potential energy turned into kinetic energy

do all cells have external flagella?

no some are internal

spirochetes

internal polar flagella that wrap around periplasma space

some spirochetes have flagella in?

the periplasm

non flagellar motility - 2 types

gliding motility and twitching motility

gliding motility

smooth sliding over a surface

twitching motility

slow, jerky process using (pili)

both gliding and twitching motility are energy dependent, what kind of energy does twitching motility use?

hydrolysis of ATP

myxobacteria is a kind of bacteria that produces?

slime layers

how does twitching motility work?

extends pili, attaches to surface, pulls themselves and repeat

just because you have pili does that mean you do twitching motility?

no, twitching motility is a secondary function of pili that some bacteria formed

polymerization of actin

for propulsion of bacteria into adjacent cells

is polymerization of actin energy dependent?

yes