Viruses/Prions Flashcards
4 components of a virus?
protein, nucleic acids, lipids, sugars
What is a virion?
entire virus particle
Envelope vs capsid?
envelope = external lipid membrane present in some viruses; capsid = all viruses have it, protein coat
What is a nucleocapsid?
some viruses have this special protein coat around nucleic acid
What is a capsomer?
Subunit that makes up a capsid
Protein coats can be ___ or ___ in shape? Which can hold more nucleic acid?
icosahedral or helical (open); helical has no theoretical limit to amount of DNA that can be packaged
mRNA would indicate a _____ sense strand
positive
Which sense strand can be immediately made into viral proteins?
positive
Which sense strand virus has to bring its own RNA dependent RNA polymerase?
negative
Which kind of viruses are more prone to errors, RNA or DNA?
RNA - no proofreading function so more mutable
Phases of viral replication kinetics?
Inoculation, eclipse, burst
Before uncoating in the cell, a virus must do what?
attach to cell membrane receptor and be taken into cell
What kinds of genes do viral genomes not possess?
Genes encoding protein synthesis machinery, energy metabolism, and membrane biosynthesis
What are the spikes you tend to see on enveloped viruses?
Glycoproteins that have been encoded in viral genome, can be used for docking to cell
GI tract pathogens - enveloped or nonenveloped?
Nonenveloped because acid destroys lipids
Naked viruses are more likely to be released in what manner?
Through lysis
Which viruses are more sensitive to heat, acids, and drying? Enveloped or naked?
Enveloped
5 ways that viruses can be categorized?
Virus family, disease process/site of infection, route of transmission, genome type, ability to establish latency
What way of categorizing viruses is most useful for public health measures?
By route of transmission!
Epstein Barr is from what family of viruses?
Herpesvirus
Are herpesviruses enveloped or naked? What kind of genome do they have?
enveloped; dsDNA
“Cold sores” are mostly associated with…
HSV1 (some HSV2)
VZV can reactivate as…
shingles
Which is more contagious, shingles or varicella?
varicella
Which viruses are associated with infectious mono?
Mostly EBV but also CMV
Genome of influenza A?
segmented RNA
Influenza A - enveloped or naked?
enveloped
Why is HIV called a retrovirus?
reverse transcriptase activity; RNA to DNA (integrated) to RNA again
2 main prion diseases in humans?
Kuru and CJD
Why do prion diseases produce spongiform encephalopathies?
plaque formation/accumulation in brain
Transmission of CJD is usually ____ or ____
iatrogenic or inherited
