General features of virus multiplication Flashcards
adsorption
attachment to the host cell
penetration
entry into the host cell
decapsidation
nucleic acid release
eclipse
expression of the genetic information
translation, transcription and NA replication
maturation
assembly of progeny virions
release
evacuation from the host cell
Viral multiplication cycles and n.
102 – 106 virion/cell
new cells, new cycles
log phase
For adsorbtion cell surface receptor and antireceptor are always needed
FALSE, only the surface one is obligatory
A cell surface is needed for the cellular functions
TRUE
sometimes non-related viruses have the same receptor
TRUE (CAR - coxackie-adeno receptor)
viruses adapt the cellular surface receptors during their evolution
TRUE
specificity - determined by the…?
tissue or species receptor protein
penetration is not energy dependent
FALSE, it is
general forms of penetration are
translocation, endocytosis and membrane fusion
translocation is…
a penetration type „trapdoor” mechanism
endocytosis is mostly used by…?
most non-enveloped viruses + herpes, pox
membrane fusion is used ONLY by…?
enveloped viruses
during membrane fusion only the nucleocapsid gets into the cytosol
TRUE
penetration alternative forms are?
injection, sexfimbria, passive
passive penetration occurs in..?
plant viruses
cellular wall injuries, arthropod bites
decapsidation is not dangerous for the virus
FALSE, it is but it is necessary
strategies for decapsidation
Use of cellular proteases
Viral uncoating proteins
Partial decapsidation (hiding the NA till the early v. P prod.)
simultaneous penetration and decapsidation (injection, translocation)
Maturation
Glycosylation, dimer formation, antigen development
at the ER, Golgi
Virus assembly usually at the site of replication
TRUE, for better protection
RNA viruses + Pox, Asfarviridae assemble in the…
cytoplasm
most DNA viruses assembly in the….
nucleus
Methods of assembly…
icosahedral
helical
Icosahedral method of assembly is…
when nucleic acid enters into the capsid
Helical method of assembly is….
when capsomers surround the nucleic acid
envelope and matrix proteins are acquired from cellular membranes
TRUE
The assembly is regulated by
scaffolding proteins
Virus releases types
cytolysis (non-enveloped)
budding (enveloped)
cytolysis can be
rapid (picorna)
slow (parvo)
apoptosis (adeno)
budding can be rapid and slow
TRUE,
rapid (Togav., Paramyxov., Rhabdov.)
slow (Arenav., Retrov.)
Cell-associated viruses release at cell death or injuries
TRUE
Cell fusion (syncytium formation) is a safe way for the spread of….?
Herpes and paramyxo
