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Encyclopedia: Virus (Site not responding. Last check: 2007-10-21) |
 | | Virus particles comprise a nucleic acid genome that may be either DNA or RNA, single- or double-stranded, and positive or negative sense. |
 | | This complex of protein and nucleic acid is called the nucleocapsid, and, in the case of the measles virus, is enclosed in a lipid "envelope" acquired from the host cell, in which virus-encoded glycoproteins are embedded. |
 | | As in the helical viruses, the spherical virus capsid may be enclosed in a lipid envelope, although frequently spherical viruses are not enveloped, and the capsid proteins themselves are directly involved in attachment and entry into the host cell. |
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