thumb|upright=1.5|[[Hepacivirus virion. The outer shell (capsid) of this virion consists of repeating simple faces, each built from three protein dimers.]]
A virion (plural, viria or virions) is an inert virus particle capable of invading a cell. Upon entering the cell, the virion disassembles and the genetic material from the virus takes control of the cell infrastructure, thus enabling the virus to replicate. The genetic material (core, either DNA or RNA, along with occasionally present virus core protein) inside the virion is usually enclosed in a protection shell, known as the capsid.
While the terms "virus" and "virion" are occasionally confused, recently "virion" is used solely to describe the virus structure outside of cells, while the terms "virus/viral" are broader and also include biological properties such as the infectivity of a virion.
Spikes
Spikes (peplomers) can protrude from the capsid, as in the Coronaviridae, the Tectiviridae, and others. These are used to establish contact with the host cell.
In viruses of the genus Chlorovirus, the virions have a single spike that serves as an injection device; an extendable injection apparatus are found in virions of the family Tectiviridae.
Viral envelope
In many virus species, the virion also has an outer membrane, the viral envelope.
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