Microbiology Flashcards
cell type:
helminth
eukaryotic
cell type:
protozoa
eukaryotic
cell type:
fungi
eukaryotic
cell type:
bacteria
prokaryotic
cell type:
viruses
noncellular
semiliving
cell type:
prion
noncellular
only a protein, not living
cell contents:
helminths
cytoplasm
energy metabolism
protein synthesis
BOTH DNA and RNA
cell contents:
fungi
cytoplasm
energy metabolism
protein synthesis
BOTH DNA and RNA
cell contents:
protozoa
cytoplasm
energy metabolism
protein synthesis
BOTH DNA and RNA
cell contents:
bacteria
cytoplasm
energy metabolism
protein synthesis
BOTH DNA and RNA
BOTH DNA and RNA
BACTERIA
HELMINTHS
FUNGI
PROTOZOA
viruses cell contents
EITHER DNA or RNA
one nucleic acid
cell contents:
prion
NO nucleic acid
neither DNA or RNA
how do prions cause disease?
they are a misfolded protein that causes disease via accumulation
(eventually causing death)
long incubation period, so could be a long time before you see symptoms
accumulation
eventually enough normal proteins will be misfolded so disease symptoms appear
they enter normal neural tissue and cause them to convert to prions as well
outcome of prion disease?
death
100% fatality
stability of prions
they are extremely stable
resist denaturation (can’t sterilize) and if even partially damaged, they can renature
prion diseases in humans
Kuru
CJD
bovine spongiform encephalopathy
familial fatal insomnia
Resistance to denaturation (in depth)
Don’t have a nucleic acid so they are unable to be sterilized
resistance to heat, proteases, and radiation
can renature and become infectious
viruses can infect____
all life forms
most abundant pathogen
Size of viruses
VERY small
1/100th of a bacterium
largest virus
POX
virus
obligate intracellular parasite that relies on the host for replication and protein synthesis
viruses depend on host
obligate intracellular parasite
no self metabolic processes
need them for replication and protein synthesis
assemble within host cell
Co-concurrence
which virus displays co-concurrence?
dependence on another virus to produce an active infection
ex. Hep D depends on Hep B for replication
basic structure of a virus
nucleic acid
capside
nucleic acid (either DNA or RNA) wrapped in protein nucleocapsid
Envelope and survival
envelop = less stable in environment
NO ENVELOPE = better survival in environment
transmission method for enveloped viruses
parental
genital/respiratory
transmission method for non enveloped viruses
fecal/oral
Methods of viral entry to cell
- endocytosis (receptor mediated or pinocytosis)
- fusion
- direct penetration
which type of viruses enter cell via endocytosis?
ex.
non enveloped viruses
Hep C, polio
receptor mediated endocytosis
virus replicates the signal required by the host’s cell receptor
the receptor then brings the virus into the cell allowing it to infect
fusion
enveloped viruses
HIV, Herpes Simplex
viruses comes to and merges with cell membrane, opens its envelope to release its contents into the cell
penetration
least common of all three
non enveloped viruses
needle spring like action
doesn’t open the cell membrane, just pushes thru
examples of endocytosis viruses
Hep C
Polio
examples of fusion viruses
HIV
herpes simplex
examples of penetration viruses
bacteriophages RNA viruses (myxovirus)
three ways viruses cause disease:
- lyse host cell
- invoke immune response that causes disease
- cause neoplastic formation of cells
ex. of virus that lyses host cell
influenza
ex. of virus that invokes immune response (immune response is cause of disease)
Hep B
ex. of virus that causes formation of neoplastic cells
HPV –> cervical cancer
mechanisms for evading host cell (4)
- replicating inside host cell, to avoid the immune cells in blood
- intracellular bridges to infect neighboring cells
- Persist in inactive form for long periods of time (latent) ex. HIV, herpes
- Gene rearrangements (development of new strains ex. influenza
productive v. latent infection
a productive infection is one that invades the cell and causes disease immediately
latent infection comes into the cell and lies dormant for an unknown amount of time (with no function) and appears when immune system is weak or time is right
4 groups of protozoans
- amoebas
- flagellates
- ciliates
- sporozoans
classification based on movement
amoebas
movement via pseudopods
entamoeba histolytic (amoebosis)
Sporozoans
movement via gliding
plasmodium falciparum (malaria)
Flagellates
giardia lambilia (giardia)
movement via whip like tail
cilliates
movement via cilia (hair like)
balantidium coli
Life cycle stages of protozoan
trophozoite
cyst
trophozoite
MOTILE
feeding, reproducing, can be seen by immune system
sensitive to environment
cyst
NON MOTILE
non metabolizing, non reproducing
survives well in environment outside of host
involved in transmission
Most common cause of disease in developing world
helminths
Host req. of helminths
helminths req. 2 hosts:
definitive and intermediary
life cycle of helminths
- egg
- larvae
- adult
detection method for helminths
O&P
O & P
examines the stool for ova (egg) and parasite (larva and adult)
2 groups of helminths
flatworms (segmented)
Nematodes (nofsegmented)
2 groups of flatworms
tapeworms
flukes
tapeworms
scolex with flat body and multiple segments
suckers on head attach to host, tail produces eggs that are shed
ex. of tapeworms
taenia sodium
taneisis via raw pork
Flukes
not common in the US
found in tropical areas (southeast asia)
often found in blood
ex. of fluke disorder
Schistosoma- schistomyesis
river rash
flukes climb in, irritation at entry point
nematodes
round body with complete digestive tract
nofsegmented
separate sexes (lg. females)
intestinal nematodes
enteobius/pinworm
ascaris/great roundworm
ancylohstoma/lesser roundworm
strongyloids/hookworm
cell walls of fungi contain (3)
ergosterol
chitin
polysaccharides
target of anti fungal medication
ergosterol
in our cells we have cholesterol, so anti fungal targets this
how do fungi proliferate
mostly asexually
budding
hyphae
spore formation
prep used for fungi
KOH
eliminates all cell debris but fungal cell wall
metabolism of fungi
either obligate or facultative aerobes
ALL req . carbon
forms of fungi
- yeast
- mold
- dimorphic
yeast
form round or ovoid cells
reproduces via budding
candida, cryptococcus
mold
tubular structures (hyphae) that grow by extension
aspergillus, zygomycetes
Dimorphic
either yeast or mold depending on environment
histoplasma, coccidioides, blastomyces
condia
asexual spores that fungi use to reproduce
4 types:
- arthrospores
- chlamydospores
- blastospore
- sporangiospore
arthrospores
fragmentation at ends of hyphae
chlamydospores
rounded, thick walled
candidia
blastospores
formed by budding of yeasts
sporangiospores
formed within sac on stalk by molds
bacterial genome
single chromosome of circular DNA
found in nucleoid
reproduction method of bacteria
binary fission
one parent cell produces two daughter cells
doubling time
the amount of time it takes for one parent cell to divide into two
depends on bacteria
e. coli = short, 18 min
myco. leprae = longest
what element is req. for growth of bacteria?
iron
essential for cytochromes and other enzymes
energy source of bacteria
fermentation of sugars into lactate or pyretic acid
can be used to identify strain
how do bacteria cause disease?
production of toxins (endo- or exo-) or by induction of inflammation
smallest bacterium
mycoplasm
size of lgst. virus
classification of bacteria based on what: (3)
response to oxygen
morphology
cell wall
classification of bacteria based on oxygen/examples
3
obligate probes/m. tuberculosis
facultative anaerobes/e.coli
obligate anaerobes/clostridium tetani
classification based on morphology (4)
cocci (spheres)
bacilli (rods)
spirochetes (spiral)
pleomorphic
arrangements of bacteria (3)
streptococci – chain
staphylococci – grape like cluster
diplococci – paired
what composes the cell wall of bacteria?
peptidoglycan
ONLY in bacteria
which bacteria doesn’t have peptidoglycan?
mycoplasm
peptidoglycan
sugar backbone with peptide side chains
cross linked by transpeptidase
transpeptidase
crosslinks the glycan and peptide in peptidoglycan
target of antibiotics like penicillin
gram +
THICK peptidoglycan
techie acid fibers
dyed blue, purple
gram -
THIN peptidoglycan
LPS layer –> endotoxin
periplasmic space
stains pink/red
periplasmic space and antibiotics
only in Gram -
has B-lactamase enzymes that degrade the b-lactam drugs
list of bacterium that won’t show up on gram stain:
Mycobacterium treponema pallidium mycoplasma pneumonia legionella pneumophilia chlamydiae/rickettsiae
why won’t it gram stain, alternative?
mycobacterium
high lipid in cell wall
acid fast stain
why won’t it gram stain, alternative?
treponema pallidum
too thin to see
dark field microscopy
why won’t it gram stain, alternative?
mycoplasma pneumoniae
no cell wall bc very small
why won’t it gram stain, alternative?
legionella
doesn’t take up the red stain
why won’t it gram stain, alternative?
chlamydiae/rickettsia
intracellular, very small
giemsa stain
