For non-enveloped viruses the host recognition sites are located on the nucleocapsid. The protein and nucleocapsid compose the virion. In contrast, enveloped viruses have their host recognition sites on the envelope. In this instance, the nucleic acid, capsid and envelope compose a virion. The shape of non-enveloped viruses is determined by the manner in which the protomers are arranged around the nucleic acid core.
Envelopes alter the appearance of a virion.
The nucleic acid of some viruses may be single-stranded while others may be double stranded. Progeny are released when the host cell is lysed, obviously resulting in host cell death. Other viruses can infect and produce progeny without destroying the host cell. Even more, there are some viruses that produce no virions when they infect host cells. The virus must attach itself to a susceptible cell.