In each case there may be more than one correct answer. Viruses are obligate intracellular parasites. Viruses are surrounded by a lipid bilayer called an envelope.
Viruses utilize double-stranded DNA genomes at some point in their life cycle.
Among the viruses, some have DNA genomes and some have RNA genomes. Viruses must attach to susceptible host cells as a first step in their reproduction. Interferon produces an antiviral state in cells. This happens when interferon a. binds to a receptor on the cell and prevents virus entry. Synthesis of viral RNA by a host cell enzyme.