Biological characteristics of the aids virus: biology of viruses. Virus particles are microscopic and visualized with electron microscope. Viruses depend on the host cell for energy and low mw precursors for the synthesis of viral components. Virus particles leave infected cells and infects other susceptible cells. Nucleic acid: dna or rna; not both. Could be single-stranded (ss) or double-stranded (ds: proteins. For(cid:373) a (cid:862)coat(cid:863) or coveri(cid:374)g called capsid. Aid in virus entering cell: lipids. May have a lipid membrane surrounding the viral particle (cid:862)e(cid:374)velope(cid:863) (this surrounds the capsid); they have spikes on the outside that act as the receptors. Proteins also in envelope: classification of hiv. Hiv contains a single stranded rna genome: retrovirus; rna > dna > rna > protein.