Processes of Life in Unicellular Organisms

Homeostasis

* Living organisms keep their internal environment within a certain range (stable internal condition) despite changes in external environment.

Metabolism

* The sum of all the chemical reactions in a cell

Nutrition

* Autotrophs: use external energy sources to synthesize carbon compounds from simple inorganic substances
* Heterotrophs: use carbon compounds obtained from other organisms to synthesize carbon compounds they require

Movement

* Sessile: organisms stay in one place
* Motile: organisms that are mobile

Excretion

* process in which metabolic waste is eliminated from an organisms

Grow and/or Develop

* Growth: The increase in size and mass of an organism
* Development: The transformation of the organism through its lifespan (usually involved hormones)

Response to Stimuli

* all life can recognize and respond to changes in environmental conditions.

Reproduction

* Sexual reproduction: involves two parents and the fusion of haploid sex cells from each parent
* Asexual: involves only 1 parent