Classification of Archaea

Classification of Archaea

Classification of Archaea

Archaea are found in extreme and harsh environments like hot springs, oceans.

They are classified  based on energy sources and metabolism.

Archaea exhibit a variety of chemical reactions in their metabolism and use many sources of energy.

These reactions are classified into nutritional groups, depending on energy sources. All of the groups use organic compounds or carbon dioxide fixation as carbon source.

1. Phototrophs

Energy source is sunlight.

Example :  Halobacterium  salinarum

 Many metabolic pathogens are occurred for example, they use a modified form of  glycolysis or citric acid cycle.

Phototrophic archaea use light to produce chemical energy in the form of ATP.

 In halobacteria, light - driven proton pump like bacteriorhodopsin generates ion gradients by pumping ions out of the cell across the pm.

The energy stored in these electrochemical gradients is then converted into ATP by ATP synthase.

2. Lithotrophs

Energy source is inorganic compound (sulfur, ammonia).

Example : Methanobacteria, Pyrolobus.

 They are nitrifiers, methanogens, anaerobic methane oxidizers.

 By redox reaction, the energy released generates ATP through chemiosmosis.

3. Organotrophs

Energy source is organic compounds.

Example : Pyrococcus,  Sulfolobus.

Classification of Archaea

Written By

Sadia Akhtar
Student of Department of Microbiology
Jagannath University.
Email- sadiabd810@yahoo.com