influenza (enveloped)

adsorption

haemagglutinin glycoprotein binds to sialic acid (specific receptor) on host membrane

penetration

invaginates → receptor mediated endocytosis → fuses with memb of endosome → releases nucleocapsid into cytosol

replication

virus genome acts as template for viral RNA-dependent RNA polymerase → comp (positive sense) RNA strandscomp RNA strands template for new copies of RNA genome (RNA-dep RNA polymerase) mRNA production of proteins using host cell organelles → capsid proteins and glycoproteinsvesicles transport HA and neuraminidase proteins to host CSM

maturation

capsid proteins transported back into nucleus for self assembly with viral genometransported to host CSM with haemagglutinin and neuraminidase incorporated

release

bud with envelope derived from host CSMsialic acid residues cleaved from surface of new viral proteins through neuraminidase → facilitates release of viral proteins