Organism

In biology and ecology, an organism (in Greek organon = instrument) is an assembly of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life.

Viruses

Viruses are not typically considered to be organisms because they are not capable of independent reproduction or metabolism. However, according to the United States Code, they are considered to be microorganisms in the sense of biological weaponry and malicious use. This controversy is problematic, though, since some parasites and endosymbionts are incapable of independent life either. Although viruses do have enzymes and molecules characteristic of living organisms, they are incapable of surviving outside a host cell and most of their metabolic processes require a host and its 'genetic machinery'. The origin of such parasites is uncertain, but it appears most likely that they are derived from their hosts.

Related Topics:
Viruses - Reproduction - Metabolism - United States Code - Parasite - Endosymbiont - Enzyme - Host cell

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