A virus is a unique microscopic agent that does not fit neatly into the biological package we call a cell. A cell has:
- Defined cellular structure with organelles
- Metabolic infrastructure and function – The ability to convert consumed non-living materials into biological energy and cellular components
- Homeostatic controls – The ability to regulate the internal environment
- Reproductive capacity – The ability to produce offspring
- Responsiveness – The ability to respond to external stimuli and conditions
- Capacity for growth
- Capacity for adaptation – The ability to alter form, function, or both over time in response to environmental challenges
A virus is structurally and fu...