Microbio Unit 2 Exam
Learn
Practice Test
Spaced Repetition
Match
Flashcards1/256
There's no tags or description
Looks like no tags are added yet.
257 Terms
what’s a virus classified as?
obligate intracellular PARASITE
HOST + cell type specific
what’s a virion?
infectious particle that viruses package into! to TRANSMIT to next cell/org!
what are the parts of a virion?
viral DNA/RNA genome
capsomeres
what’s a nucleocapsid?
capid + genome
what does the virion genome look like?
DNA/RNA
single/double stranded
together/ in parts
what are the two packaged types of virus?
naked = JUST capsid (made of capsomeres)
enveloped = host membrane envelope on the outside w/ GLYCOPROTEINS from host
what’s the “4 steps” in the hierarchy of virus classification?
family (viridae), subfamily (virinae), genus (virus), species
what are the 3 ways that a virus differs from a cell?
SINGLE type of genetic material (DNA OR RNA)
don’t have genes to make energy / proteins → HIJACK host cell
synthesize + ASSEMBLE components, do NOT grow + divide
what are the 6 steps of the infectious cycle?
attach
penetrate
uncoat
synthesize (pro’s)
assemble
release
what part of the virus determines which types of cells it can infect?
spike glycoproteins!
what is the “host range”?
what’s it DETERMINED by?
the RANGE of host org’s that a particular virus species INFECTS
determined by HOST cell’s receptor proteins
viruses r pretty choosy, so the range is usually small.
what is “cell trophism”?
virus’ preference for infecting a SPECIFIC cell type
ie HIV virus likes T cells.
what do viruses convert their genomes into? why?
CONVERT virus genome into mRNA
so host RIBOSOMES can translate them!
what are viral genomes copied by?
HOST cell polymerase
(sometimes by VIRAL polymerase)
can a host cell translate (-) ssRNA?
NOPE.
what is (+) ssRNA?
aka?
host cell CAN directly translate.
sense RNA & messenger RNA
what’s (-) ssRNA? aka?
antisense RNA
(literally just complimentary to (+) ssRNA)
how is DNA translated?
IT’S NOT.
must be transCRIBED into (+) ssRNA first
for a virus to replicate, what does it need to do?
make PROTEINS
REPLICATE genome
if RNA poly reads (+) ssRNA, what does it make?
(-) ssRNA!
if DNA poly reads (+) ssRNA, what does it make?
(-) ss DNA
what do polymerases do?
make COMPLEMENTARY strand to TEMPLATE strand
what do human RNA poly’s do?
use DNA template to make (+) ss RNA
what do human ribosomes translate?
(+) ss RNA into PROTEINS
wtf does the virus do with (+) ss RNA
host ribosomes can translate directly
OR viral RNA poly turns it into (-) ss RNA
to make TONS of (+) ss RNA
wtf does a virus do with (-) ss RNA
viral RNA poly turn it into (+) ss RNA
→ human ribosomes translate it
can also make TONS of (+) ss RNA
fill in the arrows AND boxes
(-) single stranded goes thro VIRAL rna poly into (+) ssRNA → protein
double stranded RNA - viral RNA poly —> (+) ssRNA → protein
what does human DNA poly do?
uses DNA template
makes COMPLEMENTARY DNA strand
human RNA poly…
uses DNA template
makes (+) strand of RNA
(+) RNA …
TRANSLATED by human ribo’s into proteins
what’s special ab DNA viruses?
can use HOST enzymes to make proteins.
what do DNA viruses do to double stranded DNA?
tscribe into (+) ss RNA → protein
what do DNA viruses do to ss (-) RNA?
turn into DOUBLE STRANDED DNA → ss (+) RNA → protein
what do DNA viruses do to ss (+) DNA?
turn into DOUBLE stranded DNA → ss (+) RNA → protein
what type of genome do retroviruses have?
what intermediate do they use?
have (+) ss RNA genomes
use DNA intermediate to replicate
fill in the blank
why are there so few antiviral drugs available?
viruses REPLICATE in human cells → could damage human cells
viruses r hella simple → what do the drugs even target?
how do viruses assemble?
new components hop into PROGENY virions that later get released
how do enveloped and nonenveloped viruses release?
non-envelope → cell lysis
envelope → budding off (take host cell mem with them!)
what happens in an abortive infection?
viruses just sit there in the host cell, no offpsirng are made
what happens in a chronic infection?
virus infects host cell, makes babies, but DOESN’T kill host cell until it’s time
what happens in an lytic, acute infection?
the host cell dies and the babies are released
what are the 2 pathways that happen to the virus/ host cell in the latent state?
INTEGRATE in host cell genome
stays as CLOSED circular episomes on the side of the cell
which can later be activated…. ooooo
what are the 2 types of testing can you use to detect viral infections?
what do they really detect?
ELISA, serological tests (COVID rapid)
detect antigens/ antibodies
MOLECULAR tests (PCR)
genomic SEQUENCES + PROTEINS
what are 2 NON testing ways to detect a viral infection?
what’s the limitation of the second?
symptoms of infection
cultiVATE virus + look for cytopathic effects (damage to cells)
canNOT grow on agar
wtf are prions?
what is their genome?
how do they do bad things?
infectious proteins
NO nucleic acids
make INSOLUABLE fibril aggregates (clumps)
what happens in transmissible spongiform encephalopathies?
what are the symptoms?
the prion clumps make HOLES in brain tissue
lose coordination, bad memory, coma, death
what is BSE/ mad cow disease, chronic wasting disease, scrapie sheep, vJCD (variant Jakob disease)
transmissible spongiform encephalitis (prion disease)
what are the 2 types of folded prions?
PRP-C: normal cellular prion on cell surface
PRP-SC: SCrapie, misfolded → accumulates in brain cells to make plaques, dangerous
how do prions reproduce?
MISFOLDED PRP-SC prions misfold other proteins into the infectious form.
what eukaryotic orgs are multicellular EXCEPT at reproductive stages?
why is this significant?
helminthes = parasitic worms (the eggs + larva are unicellular)
diagnose whether someone has parasitic infection based on whether u can see the eggs!!
what eukarytoic microbes are ALWAYS unicellular?
protozoa (parasites)
what eukaryotic microbes can be unicellular OR multicellular?
fungi!
what’s the unique feature about eukaryotic cells?
they have a NUCLEUS!
fungi are eukary/prokary?
aerobic/ anaerobic?
size compared to bacteria?
motile?
eukary
majority OBLIGATE aerobes, some facultative aerobes (aka WANT o2)
LARGER than bacteria
NON-motile bc no flagella.
what is special about the fungi cell structure?
have CELL WALL.
what is the distinguising component of the fungal cell membrane?
ergosterol (fatty acid)
what are the 3 components of the fungal cell wall?
B glycans
mannoproteins
chitin!
what’s fancy about B glycans and mannoproteins?
they make up the exoskeleton of crabs + arthropods.
what are some properties of chitin? why? what is it found in?
found in fungi cell WALLS.
tough, rigid, strong bc H bonds.
what are the 2 types of fungi? and some examples of each?
macroscopic: mushroom, puffball, gill
MICROscopic: molds, yeasts
what types of environments are fungi found in?
found in soil or water w/ ORGANIC MATTER
(gotta eat somehow)
how do yeast vs mold look on incubating plates?
yeasts (unicell) = round, pasty (doughy), mucoid colonies
MOLD (multicel) = hairy, wooly, fuzzy
are yeasts round/linear?
how do they move around?
round
NONmotile!!
how do yeasts reproduce?
ASEXUAL reprod
budd off to form CONIDIA
how do hyphae reproduce?
asexual AND sexual
most fungi are…
MULTICELLULAR molds
(versus single cellular yeasts)
what are the cells of MULTICELLULAR mold called? how are they shaped?
LONG filamentous cells called HYPHAE
(responsible for how hairy mold is)
what types of fungi are motile?
PLOT TWIST.
neither yeasts NOR hyphae molds are motile.
wtf are mycelium? what is their texture like?
a MASS of hyphae
hairy, cottony, velvety
how do multicellular molds grow?
spore grows a FILAMENT, turns into a hypha, and BAM a mass of hypha together = mycelium.
how do molds “eat” in order to grow?
secrete CATABOLIC ENZYMES to absorb nutrients from their environment
how do molds reproduce?
release BILLIONS of spores that reproduce sexually or asexually!
(long version: spore lands, grows into germ tube, makes submerged + surface hyphae into a mycelium clump, release more spores!)
wtf is thermal dimorphism in the context of molds?
cold temp = mold
warm temp = turn into YEAST.
basically the environment differentiates the fungi into either yeast or mold.
wtf is a mycose?
human FUNGAL disease
how common is it for mycoses to move from human to human?
NOT common.
what are the 2 most common human mycoses and what are they caused by?
MYCOSES (fungi disease)
dermatophytes = toenail fungus
candida albicans = yeast infections
how are most individual cases of human mycoses commonly happen?
INHALATION
trauma to SKIN.
how do most MASS cases of human mycoses commonly happen?
mass exposure due to ENVIRONMENTAL conditions (ie construction site)
what does it mean for a fungi to be a “true pathogen”? how common is this?
VERY rare.
they have to actively ATTACK and INVADE non-compromised tissues
in what cases will an opportunistic fungi attack?
COMPROMISED immune sys
fungi ACCIDENTALLY contaminates sterile tissues ie IV, sugery
how do true fungal pathogens cause lung infections?
airborne spores are INHALED then spread to other organs.
ie CNS, skin, lymph nodes
what are 3 ways that we identify fungi?
ISOLATE on a media
molecular (PCR) to detect genomic sequences
microscope hehe
how do parasites get into the body?
they are EXOGENOUS = must come from OUTSIDE the body
ingestion (soil, water, food)
penetration (MOSQUITO)
why don’t we have a lot of anti-parasitic drugs?
they have TONS of side effects
what is the parasitic cell covering made of?
ONLY cell membrane, NOT cell wall.
what’s the difference between protozoa + helminthes? (hint: 3 things)
prot: single cell, smaller (microscopic), CYST FORM = less metabolically active
helm: multicell, larger (some have ORGANS), lay EGGS
what is the outer coating of protozoan cells?
are they motile?
NO cell walls?
YES motile. have cilia + flagella + pseudopodia
how do protozoans affect human bodies?
infect intestinal / urogenital
infect blood cells + tissues
in protozoan reproduction, what is the first stage called? what does it do? where does it exist?
trophozoite: MOTILE in the host, eat + reproduce
what is the dormant resting stage of the protozoan reproduction? when does it kick in?
CYST stage. during bad weather!
IMmotile, NOT replicating, resistant AF, usually OUTSIDE the body
what processes are apart of the excystment and encystment? which is inside the body, and which is NOT?
excystment = INSIDE human body (cyst turns into ACTIVE trophozoite)
eNcystment = OUTSIDE human body (active trophozoite hybernates into dormant cyst)
how do helminthes damage human hosts?
ROB host of nutrients → weakness + disease
where are helminthes most commonly found?
developING countries
how are helminthes commonly aquired?
ingestion of larvae or eggs in FOOD
soil/water
insect vectors (rare)
what’s the most common worm infection in the US? how about in the rest of the world?
US = enterobius (~300 mil)
the world = ascaris (~800 mil)
how do we usually identify helminthes?
MICROSCOPE.
look for eggs, worms, or larvae in:
blood, poop, sputum, biopsies
