composition of a virus
RNA or DNA core, a protein coat, and sometimes a surrounding enveloped
Viruses lack ________________
independent metabolism
how many phases of existence for a virus
2
what does sense RNA mean
encodes proteins that can be directly translated
what does anti - sense RNA mean
encodes the complement to the encoding sequence - must be transcribed first
does an infection always lead to the death of the infected cell
no
5 steps of virus life cycle
virion entry
uncoating
gene expression and protein synthesis
virus genome amplification
virion assembly and egress
susceptible cell
has the receptors to let a virus in but it might not support the rest of the replication cycle
resistant cell
lacks the functional receptor so a virus cannot infect that cell - but it might have what it s=needs to replicate
permissive cell
has the capacity to replicate viruses but might nit have the virus receptor
what kind of cell can take up and replicate a virus
susceptible and permissive cells
what was the first virus discovered
tobacco mosaic virus
what virus grows in humans and chimpanzees only
HCV
where are viruses often grown
embryonate chicken eggs
primary cells
living tissue (plant/animal)
cannot replicate forever
immortalized cells
derived from primary cells but often mutated
can replicate endlessly
what is a cytopathic effect (CPE)
a viral infection that changes the way that a cell looks in a culture
whats syncytia
fusion of cells
what do you need for syncytia
viral attachement protein
receptor
3 ways to quantify viruses based on infectivity
plaque assay
end point dilution assay
one step growth curves
3 ways to quantify viruses using physical methods
electron microscopy
antibody based methods
nucleic acid based methods
physical methods vs infectivity
physical methods just tells us how many cells are there rather they are infectious or not - infectivity gives us how many are truly infectious
what is put in a plaque assay to contain where viruses go
semisolid agarose
what is a section of dead cells called
a plaque
