virion
Noun: 1. A complete, infectious viral particle outside a host cell: In virology, a virion is the entire, extracellular form of a virus. It is the structure that moves between host cells or organisms. A virion typically consists of genetic material (DNA or RNA) surrounded by a protective protein coat called a capsid. Some virions also have an outer lipid membrane, or envelope, derived from the host cell.
The term "virion" is used specifically in scientific contexts, particularly virology and microbiology, to describe the physical, transmissible form of a virus. It distinguishes the inert particle from the active, replicating phase inside a host cell.
- Noun:
- Scientists studied the structure of the influenza virion under an electron microscope.
- A single virion is capable of infecting a susceptible host cell.
- The viral envelope is a key component of many virions, aiding in cell entry.
- "Naked virion": A virion that lacks a lipid envelope, consisting only of the nucleic acid core and the protein capsid.
- Picornaviruses, like the poliovirus, are naked virions.
- "Enveloped virion": A virion that possesses an outer lipid bilayer membrane studded with viral glycoproteins.
- The HIV virion is an enveloped virion.
- Virus (n): A broader term that can refer to the biological agent in all its phases (both intracellular and extracellular) or, in common usage, to the disease it causes. "Virion" is the specific physical particle.
- Capsid (n): The protein shell that encloses the viral genome in a virion.
- Nucleocapsid (n): The complex of a virus's nucleic acid and its capsid, which forms the core of a virion.
- Viral particle: A more general synonym for virion.
- Virus particle: Commonly used interchangeably with "virion."
The key distinction is between virus and virion. A virus is the infectious agent with a lifecycle that includes both extracellular and intracellular phases. A virion is specifically the stable, extracellular particle that serves as the vehicle for transmitting the viral nucleic acid from one host cell to another. It is metabolically inert.
- (virology) a complete viral particle; nucleic acid and capsid (and a lipid envelope in some viruses)