virology 3 Flashcards
Attachment
virus recognition of the target cell
binding virus attachment proteins (VAPs) on the surface of virion on the receptors on the target cell
Non-enveloped VAPs
part of the capsid or a protein extending from the capsid
Enveloped VAPs
spike/peplomer glycoprotein on the envelope
Receptor
protein, carbohydrates on glycoproteins or glycolipids on the cell surface
receptors on the host cell determine host range, tissue tropism
Penetration
3 types
entry into the cell
energy dependent, rapid
fusion
envelope
fuse with cell membrane
endocytosis
enveloped
translocation
non-enveloped virions
bind attach and simple pass through
uncoating
protective protein shell
nucleocapsid is disintegrated
genome freed in cytoplasm
protein disintegrate in cytoplasm
following uncoating synthesis of viral proteins by cellular metabolism
translation
viral RNA/protein utilize cellular machinery
viral mRNA translation to viral protein is essentially the same as cellular mRNA
posttranslational modifications
macromolecular synthesis
transcription, translation, posttranslational modification and viral genome replication
DNA viruses
replication in nucleus
most use host cell’s DNA-dependent RNA polymerase II and other enzymes to transcribe viral mRNA
RNA virus
replicate in cytoplasm: must encode or carry necessary enzymes for transcription and replication in their genomes
assembly
viral matrix protein brings viral nucleocapsid to the cell membrane
maturation
budding virion
no cellular protein on the membrane
all viral protein