Definition of Life

The outlook on life is still an unresolved question, that has been developing for many years. However, a general definition is generally accepted, which can be simplified into a few points. We call systems that:
 * are limited in time and space,
 * open – they exchange energy, substances and information with the environment,
 * material and of a uniform chemical basis – primarily carbon compounds (nucleic acids and proteins),
 * high organization – low entropy,
 * the ability to exist independently,
 * separate maintenance,
 * separate reproductions,
 * development.

The basic unit of all living systems is the cell.

It is a question of whether to consider rickettsia and chlamydia as living or non-living. They are not capable of independent life, but have preserved some metabolic pathways.

Viruses, virions, prions and transposons are considered as non-living.

Related Articles

 * Cell theory