Microbio Lec 3
Terms
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Lec 3
- Extracellular components
- name them -
- Capsules
- Flagella
- Pili and Fimbriae -
Lec 3
- Extracellular components
- Capsules and Slime layers -
- made of high mol. wt. polysac.
or protein (anthrax)
- capsule is more rigid than
slime layer
- can be seen w/ neg stain
- used for attachment and
protection -
Lec 3
- Extracellular components
- Capsules
- Function -
- Aid in attachment to organs
or environment
- aid in attachment of bacteria
to each other
- Protection from host immune
system -
Lec 3
- Extracellular components
- Flagella -
- Most common mechanism for
directed movement
- more common in gram -, but
also found in gram +
- highly conserved structure,
but can vary in # and
position
- used for classification -
Lec 3
- Extracellular components
- Flagella
- Polar -
- single flagellum at one end
- sometimes found at both ends -
Lec 3
- Extracellular components
- Flagella
- Lophotrichus -
- multiple polar flagella
- aka "tufts"
- wrap around eachother like
"tufts" of hair -
Lec 3
- Extracellular components
- Flagella
- Peritrichous -
- flagella all around the
cell
- perimyceium -
Lec 3
- Extracellular components
- Flagella
- what happens in
varying conditions -
- in varying conditions
Bacteria can have
different different # of
flagella -
Lec 3
- Extracellular components
- Flagella
- Flagella construction -
- from inside out
- 4 rings are used to anchor
at specific points
- hollow rod is inserted
through rings
- rings are protein made in
cytoplasm -
Lec 3
- Extracellular components
- Flagella
- Flagella shape -
- flagella is helical in
shape
- structure is the same for
all bacteria, but different
from Archea -
Lec 3
- Extracellular components
- Flagella
- classification -
- Flagella is classified by
distance between waves -
Lec 3
- Extracellular components
- Flagella
- propeller motion -
- can be either CW or CCW
- Fli protein designates
direction
- CCW moves foward, CW rever.
- motor makes torque by
passing H+ ions from high
conc. to low conc. -
Lec 3
- Extracellular components
- Pili and Fimbriae -
- Many short pili = fimbriae
- used for attachment &
Conjugation
- can make crawling/twitching
motion
- made of Pilins -
Lec 3
- Extracellular components
- Pili and Fimbriae
- Pilins -
- Makes up Pili
- Very sticky
- aids in attachment
- Variable genetic expression -
Lec 3
- Extracellular components
- Pili and Fimbriae
- Antigenic Variation -
- Pili are easily ID'd by
immune system
- thus, microbe can change
pilin that is expressed
- if Pilin A is ID'd, Pilin A
is turned off, then starts
making Pilin B etc... -
Lec 3
- Extracellular components
- Pili and Fimbriae
- Conjugation -
- very long pilus used in
swapping of DNA