outer cell things (flagella, pili, etc) Flashcards
what is the S-layer
-protein mesh/sieve
-permeable paracrystalline lattice
-outer most layer for the enevlope
what does the S-layer do in bacteria
-in few bacteria
-protection
-adhesion
-acts as an extra layer
what does the S-layer do for archea
-acts as the cell wall
-protects against osmotic lysis
-cell shape
what are the capsule and slime layer
-sticky poly saccharide coat
-sometimes made of protein (rare)
-outer most layer
-attachments, biofilm, protection, pathogenesis
purpose of the capsule specifically
-tight matrix
-excludes small molecules
-strongly attached to the cell
-only seen within bacteria
purpose of the slime layer specifically
-easily deformed
-loosely attached to the cell
what is the outer most layer in bacteria
we dont have enough info
pili
-found on bacteria surface
-thin filamentous protein
-multiple functions
fimbriae
-short pili used for attachment
-helps attach and cause disease
-one role
roles of pili
-conjugation (genetic exchange)
-twitching motility (type IV pili)
-pathogenicity
-adhesion
where is pili found
in most gram negative and some gram positive bacteria
flagellum
-thin protein appendages
-rotates at 1000 revolutions/sec
-60 cell lengths/sec
monotrichous
one flagella
amphitrechous
one flagella at each pole
lophotrichous
multiple flagella at one pole
peritricherous
many flagella found everywhere
movement of flagellated bacteria
-tumbling (clockwise rotation of flagella)
-running (counter clockwise rotation of flagella)
a bacteria is described as being hairy when under a microscope what is the structure
pili
flagellum structure
-filament
-flagellin
-several parts: hook, basal body
-hollow
-proton motor force
-assembles form the tip
archaellum structure
-filament
-smaller than flagella
-not hollow
-driven by ATP
-assembles form the base
-still rotates but slower
motility: twitching
-atp dependent
-type IV pili
-extend then pull
-allows to move on harder surfaces
motility: gliding
-proton motive force
-continuous and smooth motion without external propulsion
your favorite bacteria moves and you did not detect a type 4 pili of flagellum what type of motility is your bacteria most likely capable of
gliding
motility in eukarya
swimming (long structure: flagellum, short structure: cillia, which has other functions such as sweeping food)
flexile whip (microtubules in the cytoplasmic membrane, atp are the source of energy)