Biological Classification – Eubacteria (True Bacteria)

Eubacteria are characterised by the presence of a rigid cell wall which is made up of Peptidoglycan, and motile bacteria possess a flagellum which is used for locomotion.


Eubacteria includes the following types:


A. Cyanobacteria


Cyanobacteria (BGA) (blue-green algae) have chlorophyll-a similar to green plants which are found in chromatophores. Hence cyanobacteria are photosynthetic autotrophs.

·  The cyanobacteria are unicellular and exist as colonial or filamentous, marine or terrestrial forms.

·  The colonies of cyanobacteria are generally surrounded by a gelatinous sheath.

·  They form algal blooms in polluted water bodies (Eutrophication).


B. Nitrogen fixing bacteria


These bacteria fix atmospheric nitrogen in specialized cells called heterocysts, example Anabaena & Nostoc. (Heterocyst provide anaerobic condition required for N2 fixation).


C. Chemosynthetic autotrophic bacteria


·  They oxidize various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production.

·  These bacteria play a major role in bio-geochemical cycles by recycling nutrients like nitrogen, phosphorous, iron and Sulphur.


D. Heterotrophic bacteria


·  They are the mostly decomposers.

·  Some help in making curd from milk, production of antibiotics, fixing nitrogen in legume roots, etc.

·  Some are pathogens causing damage to human beings, crops, farm animals and pets.

·  Tuberculosis, Typhoid, Cholera and tetanus are some of the diseases caused by different bacteria.

Post By : Mamta Singh 01 Jan, 2019 4670 views Biology