Bacteria are of two groups eubacteria and archaebacteria. The eubacteria are commonly found in soil, water and living in or on larger organisms include the gram positive and the gram negative and the cyanobacteria. Archae bacteria are a group of ancient bacteria.They are supposed to be originated just after the origin of life on earth.
Archaebacteria: Cell structure
The basic cell structure is same except capsules are rare in Archae.
Genetic material is found free in the cytoplasm similar to that Eubacteria.
Common Bacterial and Archae Structures and their Functions
|Plasma membrane||Selectively permeable barrier, mechanical boundary of cell, nutrient and waste transport, location of many matabolic processes(respiration, photosynthesis), detection of environmental cues for chemotaxis.|
|Periplasmic space||In Gram negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient processing and uptake; in gram positive bacteria and archael cells, may be smaller or absent.|
|Cell wall||Provides shape and protection from osmotic stress|
|Nucleoid||Localization of genetic material (DNA)|
|Gas vacuole||Buoyancy for floating in aquatic environments|
|Endospore||Survival under harsh environmental conditions; only observed in Bacteria.|
|Capsules and slime layers||Resistance to phagocytosis, adherence to surfaces; rare in the Archae.|
|Fimbriae and pili||Attachment to surfaces, bacterial conjugation and transformation, twitching and gliding motility.|