The procaryotic term “ ” ( Prokaryota or Prokarya ), of the Greek pro (before) and caryon (core), is initially a reference to a cellular structure particular, without core nor others Organite S, and being opposed to the structure Eucaryote.
The procaryotic form a Taxon thus, gathering living beings of which the cells have the procaryotic structure. These organizations have enzymes located in the cellular wall and multiply by scissiparity (asexual division). This taxon is opposed to the Eucaryote S, this division of alive in two “kinds” being most fundamental (cf the reigns of alive the).
The taxon of the procaryotes is not regarded as Monophylétique: the organizations with procaryotic cellular structure are classified in Archéobactérie S or Eubactérie S, and it is considered that one or the other of these tax has a common origin with the Eucaryote S. the first procaryotes were perhaps already present at the time of the Éoarchéen (era of the Archéen), that is to say there is more 3 600 My.
The study of the procaryotes is in fact that of the Bactérie S . It especially developed at the 19th century, with work of Louis Pasteur in France and of Robert Koch in Germany. The “procaryotic” term finds all its significance in the Années 1950, when the Electron microscope watch the absence of true core in the cell.
Organization of the procaryotes
See also: bacterial Structure
The procaryotes have a cellular Paroi (Polypeptide S, Polysaccharide S) and a single DNA circular. Contrary to the cells Eucaryote S, this DNA is not associated with other proteins. The procaryotes also have Plasmide S. Contrary to the core at the cells eucaryotes, the procaryotic cell it has a filament of DNA which contains the genetic information which is not protected him by a nuclear membrane.
- Archéobactérie S
- photosynthetic Bacteria
- Bacteria chimiotrophes
- bacterial Structure
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