ph = 8-9 > subunits DISSOCIATE due to repulsion between -COO-‘s Icosahedral IONIC interactions most important Add NaCl > NH3+& PO4-neutralized > subunits DISSOCIATE pH 7, w/ RNA & Mg++> ionic bonding pH 5, w/ RNA & w/o Mg++> HYDROGEN bonds > NORMAL viral particle pH 7, w/ RNA & w/o Mg++> NO H+bonds between -COO-‘s > repulsion > viruses SWELL & S DECREASES (i.e. sediment more slowly) > subunits do NOT dissociate as RNAs hold them together pH 7, w/ 1M NaCl > ionic interactions disrupted > DISSOCIATE STEP FIVE: Divided Genome TRV – short: capsid for BOTH long & short; long: polymerase for BOTH short alone > NOT infectious long alone > disease symptoms but NO viral particles are made BMV – RNA3&4 in the same capsid; RNA4 is a subgenome of RNA3 RNA3 > dicistronic, make subgenomic RNA4 > coat protein RNA4 > does NOT replicate through RF RNA1, 2, 3 added together > INFECTIOUS (i.e. do not need 4) cf. Density: 1 > 3+4 > 2 (in equilibrium centrifugation) AMV – Polymerase of AMV requires CAPSID to become functional Naked RNA1, 2, 3 added together > polymerases ARE made
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