Viruses and Prions Flashcards
viruses are
submicroscopic infectious particles
virus characteristics
acellular (no cells)
obligate intracellular pathogens
DNA or RNA
infect all known life
no metabolism
when were viruses discovered
1898
virus size
20 - 1000 nm long
virion
single infectious virus particle
virion parts
exterior protective protein capsid
genetic material
capsid
protein shell
bulk of a vision
capsomere subunits
animal viruses can be
helical
icosahedral
complex
bacteriophage
complex capsids
attach to cell surface to inject genetic material
envelope
lipid-based
arises from budding off host cell
animal viruses may be enveloped
bacteriophages are not enveloped
naked (nonenveloped)
viruses that lack an envelope
cell lysis (bursting)
spikes
peplomers
protrusions from capside or envelope
glycoproteins
aid in attachment and entry to host cell
glycoprotein
proteins with sugars
stages of animal virus replication
- attachment
- penetration
- uncoating
- replication
- assembly
- release
attachment
naked viruses attach to host cells using capsid proteins
other viruses use spike proteins
host range
collection of species a virus can infect
tropism
range of tissues or cells a virus can infect inside a given host
specificity - “lock and key”
penetration
enveloped - endocytosis or fusion
naked - endocytosis
uncoating
capsid is digested by enzymes