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