Viruses do not share the same classification system as organisms because they are not considered to be living
- Viruses do not have metabolism and can only reproduce using the cellular machinery of an infected host cell
Viruses are classified mainly according to phenotypic characteristics, including:
- Morphology (e.g. helical, icosohedral, spherical, complex)
- Nucleic acid type (e.g. DNA = adenovirus ; RNA = retrovirus)
- Method of viral replication (e.g. lytic vs lysogenic cycles)
- Host organisms (e.g. bacteriophages)
- Types of disease caused (e.g. influenza virus, HIV)
Types of Viruses
