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The structure of a prokaryote is very much simpler than that of a eukaryote. There are no endomembranes, endosymbionts, nucleus or cytoskeleton. The DNA is carried on the genophore, a circular chromosome, in a ill defined area of the cytosol called the nucleoid. The chromosome is attached to the cell membrane during cell division (fission), frequently at a point called the mesosome.

The structure of a '''prokaryote''' is very much simpler than that of a [[eukaryote]]. There are no endomembranes, endosymbionts, nucleus or cytoskeleton. The [[DNA]] is carried on the genophore, a circular chromosome, in a ill defined area of the cytosol called the nucleoid. The chromosome is attached to the cell membrane during cell division (fission), frequently at a point called the mesosome.

#πρό-καρυον (pro-karyon) - before kernel.  

#πρό-καρυον (pro-karyon) - before kernel.  

Prokaryotes are extraordinarily diverse:

Prokaryotes are extraordinarily diverse:

Proteobacteria - Gram-negative, two cell membranes, hugely diverse, ''[[Escherichia coli]]''.

''Proteobacteria'' - Gram-negative, two cell membranes, hugely diverse, ''[[Escherichia coli]]''.

   

   

Firmicutes and Actinobacteria - Gram-positive, thick peptidoglycan cell wall.  

''Firmicutes'' and ''Actinobacteria'' - Gram-positive, thick peptidoglycan cell wall.  

Spirochaetes - helical bacteria.  

''Spirochaetes'' - helical bacteria.  

Prokaryotic DNA lacks histones (packaging proteins), although other packaging proteins are present, and molecules have easier access to DNA compared with eukaryotes. They generally have efficient genomes, with little sequence other than coding sequence or regulatory sequence. Transcription is by just one class of RNA polymerase. Transcription leads to translation with no intermediate processing, which allows several genes to be encoded in a single transcriptional unit (a polycistron). They have small (70S) ribosomes.

Prokaryotic DNA lacks histones (packaging [[protein]]s), although other packaging proteins are present, and molecules have easier access to DNA compared with eukaryotes. They generally have efficient genomes, with little sequence other than coding sequence or regulatory sequence. Transcription is by just one class of RNA polymerase. Transcription leads to translation with no intermediate processing, which allows several genes to be encoded in a single transcriptional unit (a polycistron). They have small (70S) ribosomes.

[[Category:Molecular Biology]]

[[Category:Molecular Biology]]

[[Category:microbiology]]

[[Category:microbiology]]