Viruses packet Flashcards
what kingdom and domain are viruses apart of?
none
what’s an obligate intracellular parasite?
requires host cell to reproduce inside of cell
what would make someone say that a virus is nonliving?
lacks cell membrane lacks cytoplasm lacks enzymes lacks ATP contains DNA or RNA (never both) can reproduce, but not on its own
what are the types of nucleic acid in a virus?
DNA viruses -single and double stranded
RNA viruses -single and double stranded
what measurement are viruses measured at?
nanometers
are viruses strain specific?
yes; phage typing
what are the different shapes of viruses?
helical/filamentous polyhedral cuboidal round complex
what is a colony of virus?
plaque; composed of billions of viruses originating from 1 parent virus
what does the capsid contain?
protein shell
capsomeres
what is the envelope composed of? What does it do?
optional, phospholipid bilyer, protects viruses from immune system
what are spikes used for?
adherence
optional
what would make someone say that a virus is living?
can reproduce (not by itself) contains C, H, O, N (four basic elements) has macromolecules (proteins and lipids)
what are the effects of the environment on viruses?
extreme pH and temp
what can Hepatitis B capable of doing?
withstanding boiling heat for 10 minutes
what are chick embryos used for?
vaccines and to grow large number of viruses
what are the different types of neurotrophic viruses?
rabies, polio, herpes virus
what are the different types of dermatotrophic viruses?
herpes virus, chicken pox, measles
what are the different types of viscerotrophic viruses?
hepatitis
what are the different types of pneumotrophic viruses?
rhinovirus, influenza virus
what are the cell lines pathway?
digestive enzymes out of kidney–separates cells–> petri dish with nutrient broth–7 days–> cell lines appear, add virus in petri dish –7 days–> plaque forms in petri dish with kidney cells
list plaque assay method
E. coli B———>
T4 phage ——> PETRI DISH
melted agar —>
what is a provirus?
viral DNA that’s incorporated into the host chromosome and never leaves
What happens when a provirus remains latent?
No effect
What happens when a provirus becomes active?
Goes into lytic (burst) cycle
What is scrapie?
Prion disease- neurological disease of sheep
What is kuru?
Prion disease- cannibals, mostly in women
What is mad cow disease?
Prion disease- incubation is 20 years; no cure
How do humans get mad cow disease?
The dead sheep that die from Scrapie are fed to cows, humans eat the cows
What is Creutzfeldt-Jakob (CJD) disease?
Prion disease- genetic disease in older people (60-70yrs); makes same prion in mad cow disease
What are the symptoms of prion diseases (sporongiform encephalopathies)?
Long incubation time
CNS damage
No immune response
Brain tissue looks like a sponge
What is the species to species barrier of the prion diseases?
None. It can go from one species to the next, nonstop.
What are prions?
Proteinaceous infectious particle
What are prions resistant to?
Heat, most disinfectants, UV light
How do prions act as infectious agents?
PrP* contacts normal PrP and alters and converts normal PrP into PrP*
What is the result of prions actin as infectious agents?
PrP* accumulates in brain tissue and forms plaque (spongy)
What disease is caused by prion acting as infectious agents?
Spongiform encephalopathy (large vacuoles in brain)
what happens when a provirus remains latent?
no effect
what happens when a provirus becomes active?
goes into lytic (burst) cycle
what happens to a latent infection over time?
becomes an active infection (lytic cycle)
can be spontaneous and induced
what does a provirus convert?
a normal host cell into a tumor cell
what does a provirus do?
introduce new viral oncogenes to host chromosome
what is contact inhibition?
cells stop dividing when they contact other cells
what is a characteristic of tumor cells?
loss of contact inhibition (cancer cells don’t stop dividing when they have contact with other cells)
what is a prion?
proteinaceous infectious particle
what is scrapie?
a prion disease; a neurological disease of sheep
what are prions resistant to?
heat, most disinfectants, and UV light
what happens to lethal PrP* when it contacts normal PrP?
converts normal PrP into lethal PrP* (one is changed, it changes the bunch)
what is the result of prions acting as infectious agents?
lethal PrP* accumulates in brain tissue and forms plaque (spongy lookin)
what is spongiform encephalopathy? and what causes it?
large vacuoles develope in brain, leads to death ; prions acting as infectious agents
do lethal PrP* undergo reproduction? how do they change normal PrP?
changes normal PrP by conversion, doesn’t undergo reproduction
what is Kuru?
cannibals; mostly in women
how does a person get Mad Cow disease?
the sheep from Scrapie is fed to the cows, human eat cows; takes 20 years to incubate; no cure
what is Creutzfeldt-Jakob disease (CJD)?
genetic disease in older people (60-70), makes same prions as mad cow disease
what are the symptoms/pathology of spongiform encephalopathy?
long incubation time, CNS damage, no immune response, brain looks like a sponge
what is the species to species barrier of spongiform encephalopathies?
can go from one species to another, doesn’t stop.
what happens in the lytic cycle?
burst and death of host cell, release of mature phages
how many phases does the Lytic Cycle have?
5
what is the burst time for the lytic cycle?
T4 phage- 60 minutes
what is the burst size for the lytic cycle?
200 phages
what happens in the lysogenic cycle?
host cell survives
how many phases does the lysogenic cycle have? What are they?
2; Attachment phase and Penetration phase
what happens to the prophase in the lysogenic cycle?
remains latent inserted into host chromosome
what is the temperate phage?
phage that produces prophage in the lysogenic cycle
what is the lysogenic cell?
host cell that has a prophage within its chromosome
what is lysogenic conversion?
host cell acquires new characteristics due to a prophage (new genes)
