Microbial cell structure and classification Flashcards
what in the cell are virulence factors
different cell structures
Rods
straight club-shaped
cocci
spherical
coccobacillary
very short rods
virulence factor
component of a cell or virus which enhances its ability to cause disease
flagella
required for movement of cell,
chemotaxis
movement toward or away from toxic substance
what protein makes flagella
flagellin
Monotrichous
single flagella
lophotrichous
multiple flagella coming out of one spot
amphitrichous
flagella coming out of either end
peritrichous
flagella coming out of everywhere
pili
allow cells to adhere to host cell or other bacterial cells
capsule
- thick viscous layer to thin amorphous slime layer
- usually polysaccharide confers resistance to phagocytosis
bacterial cell contents: nucleoid
area containing bacterial chromosome and plasmid DNA
bacterial cell contents: cytoplasmic inclusion bodies
nutrient macromolecules are stored as large microscopically visible complexes
bacterial cell contents:70s ribosome
site of protein synthesis
bacterial cell contents: endospores
heat-resistant, dehydrated multi-layered cells that are rich in calcium dipicolinate
sporulation
forming endospores
bacterial cell contents: plasma membrane is equivalent to what other sturcture
eukaryotic membrane
name 3 functions of plasma membrane
active transport
respiratory chain
synthesis for phospholipids, LPS
bacterial cell contents: bacterial cell envelope
plasma membrane
cell wall
intervening material
bacterial cell envelope attaches to host cells mediated by what
pili and teichoic acids (gram + only)
name 2 groups bacteria can be divided into
gram positive
gram negative
explain gram staining
- crystal violet
- Iodine dye ( both violet)
- decolorization - alcohol acetone
(+ violet, - clear) - safranin
(+ purple/blue, - red)
what are 3 main key layers of Gram + cell
peptidoglycan
teichoic acids, lipteichoic acid
plasma membrane
peptidoglycan
complex macromolecule
-glycan polymers cross-linked by peptide chains
name four functions of peptidoglycan
- diffusion of small molecules
- shape of bacterial cell
- phagocytosis
- MDP
Muramyl dipeptide (MDP) is what
product of peptidoglycan degradation in host
MDP causes what
fever
Teichoic acids
water-soluble polymers
how is teichoic acid linked to peptidoglycan
phosphodiester linkages
what are common surface antigens on Gram + bacteria
TA’s and LTA’s
Teichoic acids
Lipoteichoic acids
what enzyme is required for transport of nurtients across plasma membrane for Gram + cell
permeases
what are 4 key layers of Gram -
outer membrane
thin peptidoglycan
periplasmic space
inner plasma membrane
what is the outer memebrane of gram - compsed of
lipopolysaccharide (LPS)
where is LPS located on outer memebrane for Gram -
outer leaflet only
LPS is sometimes called what
endotoxin
besides LPS what else is located on outer membrane of Gram -
porins
brauns’ lipoprotein
omp protein
what are the 3 covalently linked sections for LPS
lipid A
Core
O antigen
lipid A role
endotoxic activity
anchors LPS
core polysaccharide structure
unusual 8 carbon sugar KDO
purpose for us for O antigen
helps us identify
LPS is shed into blood stream during bacteremia, what does it cause
synthesis of IL-1, TNF
-complement and coagulation activated
what are some clinical effects of LPS
sleep
fever
shock
hypoglycemia
LPS and lipoteichoic acid are both what
amphipathic
clincially what does lipoteicoic acid cause in the body, what does it not cause unlike LPS
coagulation
not fever
what do prions do
form channels allows passive diffusion of small charged molecules
braun lipoprotiens
anchors outer membrane to peptidoglycan
omp proteins
stabilize outer proteins
form gram -, what are 4 functions of outer membrane
permeability barrier
structural rigidity
sieve
host cell and phage attachment
how is gram - peptidoglycan different from the gram + layer
no pentapeptide briding
loss crosslinking, more porous
Perisplasmic gel contains
hydrolytic enzymes
what virulence factors are located in the periplasmic space
collagenases
hyluronidase
how are contents of periplasm released
shedding of outer membrane
what is in kingdom protista
eukaryotic and unicelluar
what is in kindgdom prokaytoia
all bacteria
most pathogens are in what family
eubacteria
kingdom prokaryota
what are 3 families in protista
protozoa
algae
fungi
what are 3 families in prokayota
cyanobacteria
archaebacteria
eubacteria
what are 2 broad classes of bacterial virulence
promote colonization
damage to host
what are adherence virulance factors
pili
adhensions
biofilms
invasins
bacterial surface proteins
allows entry into cells that are not naturally phagocytic
escape from phagocytic vesicles
- pathogens survive ingestion
- leave vesicle, intracellular life
- disrupts membran and escapes
how does Cytotoxins acquire iron
kills cell to liberate intracellular nutrients
what do capsules and slime layers do for evading the immune system
cover entire cell,
- network of polymers helps bacterial cell evade complement and phagocytes
exotoxins
toxic bacterial proteins
what are 3 types of exotoxins
AB toxins
hemolysins
superantigens
AB toxins
A and B subunit
enter cell by translocation or endocytosis
