Virus General Properties of Viruses Virus have both an extracellular and an intracellular state. a virus is a submicroscopic particle containing nucleic acid surrounded by protein and occasionally containing other macromolecular components In this extracellular state, the virus particle, also called the virion, is metabolically inert and does not carry out respiratory or biosynthetic functions. The virion is the structure by which the virus genome is carried from the cell in which it has been produced to another cell where the viral nucleic acid can be introduced. In the intracellular state virus replication occurs: the virus genome is produced, and the components that make up the virus coat are synthesized When a virus genome is introduced into a host cell and reproduces, the process is called infectionVirus General Properties of Viruses Virus have both an extracellular and an intracellular state. A virus is a submicroscopic particle containing nucleic acid surrounded by protein and occasionally containing other macromolecular components. In this extracellular state, the virus particle, also called the virion, is metabolically inert and does not carry out respiratory or biosynthetic functions. The virion is the structure by which the virus genome is carried from the cell in which it has been produced to another cell where the viral nucleic acid can be introduced. In the intracellular state, virus replication occurs: the virus genome is produced, and the components that make up the virus coat are synthesized. When a virus genome is introduced into a host cell and reproduces, the process is called infection