Internal and External to the Cell Wall Flashcards
what are slime layers?
composed of diffuse, unorganized material that can be easily removed
T/F slime layers are commonly found in medically relevant bacteria
F, in environmental bacteria
What are slime capsules?
composed of rigid, well organized layers that are tight around the cell
T/F slime capsules are commonly found in pathogenic bacteria
True
What stain is utilized to see slime capsules under an electron microscope
India Ink
What are three advantages for bacteria to have a slime capsule?
allows pathogenic organisms to hide from hosts immune system
allows bacteria to stick better to whatever surface theyre on
allows bacteria to be safe from dessication
What are fimbtiae
short, fine, bristle-like appendages
What is the function of fimbriae, up to how many can be on one bacteria
attachment mediators, make first contact with the environment, up to 1,000
T/F fimbriae are only located on one pole
false surround entire perimeter
What are pili
elongated, rigid tubular structures
T/F, pili are always present
false, formed only when organisms are close and start communicating.
what is the function of pili
exchange DNA
What is the primary function of flagella
motility
Flagella are (rigid/soft), and have a (hollow/dense) (linear/helical) structure
rigid, hollow, helical
What kind of microscope is necessary to see flagella
electron microscope
What is the monotrichous arrangement of flagella
singular flagellum on one singular pole
What is the amphitrichous arrangement of flagella?
tufts of flagella from both ends of the cell
what is the lophotrichous arrangement of flagella
tuft of flagella from one end
what is the peritrichous arrangement of flagella
flagella all around the perimeter
What are the three main components of flagella?
filament, hook, basal body
what is the filament composed of?
composed of around 20,000 flagellin proteins and a cap with 5 varying proteins arranged in a hollow helical tube
what is the function of the cap?
plays a role in attachment and filament assembly
What is the function of the hook?
connects the filament to the basal body
what is the basal body?
the motor of the flagellum
what is the function of the basal body
contains rings that supply motor proteins with a proton gradient in order to allow movement
How many rings are present in the basal body of gram - bacteria? what are they?
4, L ring, P ring, MS ring, C ring
How many rings are present in the basal body of gram + bacteria? what are they?
2, Ms ring, C ringT
T/F the flagellum grows from the base
false, grows from the tip
What is the structure and fucntion of MS and C rings?
have a helical arrangement of charges on them, move protons across motor proteins, providing the force needed to start movement
How many protons are necessary per revolution during flagellar movement?
1200 per revolution
What role do chemoreceptors play in flagellar movement
signal to the fli proteins associated with the MS and C rings to stop when bacteria are entering an unsuitable environment
How do peritrichous bacteria move?
to dart forward, flagella are bundled and rotated in a counter clockwise direction
when stopped by chemoreceptors , they tumble by pushing the flagella out in a clockwise rotation
How do polar bacteria move?
in bacteria with reversible flagella, counterclockwise to go forwards, clockwise to go backwards
in bacteria with a unidirectional flagella, clockwise to run forward, stop to turn - can only go forward
what is brownian movement?
movement in fluid
What are some features of archael flagella?
thin
filament not comprised of flagellin
dense, filled structure
Use ATp hydrolysis for energy
What is the structure of the basal body in archaea
comprised of around 12 proteins
How many different proteins is the archael filament comprised of?
7-12 different proteins
