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CBSE Class 11-science Answered

<div>URGENT...</div> <div>Dear teacher</div> <div>I need a detailed description of archaebacteria (from it's origin to its use in future etc.)</div> <div>It would be great if you could send me some links related to the topic n suggest a few videos also.&nbsp;</div>
Asked by deeptivora2000 | 25 Aug, 2016, 10:33: AM
Expert Answer

Origin of Archaebacteria:

  • It is said that archaebacteria evolved immediately after the origin of life on the Earth.
  • They are considered one of the most primitive forms of living organisms
  • They live in extreme habitats such as salty areas, hot springs and marshy places and hence are also termed evolutionary relics or living fossils.

General Characters of Archaebacteria:

  • Cell wall is non-cellulosic formed of polysaccharaides or proteins.
  • Cell membrane lipids are arranged in monolayer. The lipids have long, branched hydrocarbon chains linked to glycerol which enable these forms to tolerate extremes of heat and acidity.
  • Characteristic chemical composition enables them to bear extremes of heat and pH.

Classification of Archaebacteria:

Based on the kind of environmental conditions in which archaebacteria survive, they are categorised into three major groups.


  • Occur in marshy areas
  • Convert CO2 into methane
  • Obligate anaerobes
  • Used in gobar gas plants for the production of methane and fuel gas
  • Also found in the stomach of ruminants
  • Examples: Methanobacterium, Methanococcus


  • Grow in salt-rich conditions
  • Grow in salt pans, sea, salted fish
  • They give unpleasant odour and undesirable pigmentation to salt
  • Examples: Halobacterium, Halococcus 


  • Can live in high termperature as well as acidic conditions
  • Found in hot sulphur springs (temperature: 80 °C, pH: 2)
  • Chemosynthetic in nature
  • Examples: Thermoproteus, Thermoplasma

Economic Importance of Archaebacteria:

  • Methanogens are used in the generation of gobar gas from dung and sewage to be used as cooking gas.
  • Heat resistant thermophilic enzymes and restriction enzymes obtained from thermoacidophiles are used in biotechnology.
  • Halophiles are used in bioleaching of poor mines.
  • Archaebacteria are used in biosensors. 
Answered by Sheetal Kolte | 25 Aug, 2016, 11:39: AM