Prokaryote | Prokaryotic Cell
Definition :
The prokaryotes are a group of organisms whose cells lack a membrane-bound nucleus (karyon). The organisms whose cells do have a nucleus are called eukaryotes. Most prokaryotes are unicellular organisms, although a few such as myxobacteria have multicellular stages in their life cycles or create large colonies like cyanobacteria. The word prokaryote comes from the Greek πρό- (pro-) "before" and καρυόν (karyon) "nut or kernel". Prokaryotes do not have a nucleus, mitochondria, or any other membrane-bound organelles. In other words, all their intracellular water-soluble components (proteins, DNA and metabolites) are located together in the same area enclosed by cell membrane, rather than separated in different cellular compartments.
The division to prokaryotes and eukaryotes reflects two distinct levels of cellular organization rather than biological classification of species. Prokaryotes include two major classification domains: the bacteria and the archaea. Archaea were recognized as a domain of life in 1990. These organisms were originally thought to live only in inhospitable conditions such as extremes of temperature, pH, and radiation but have since been found in all types of habitats.
Contents
1 Relationship to eukaryotes
2 Sociality
3 Reproduction
4 Structure ( Prokaryote Structure )
5 Morphology of prokaryotic cells
6 Evolution of prokaryotes
Definition :
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| Prokaryotic Cell |
The prokaryotes are a group of organisms whose cells lack a membrane-bound nucleus (karyon). The organisms whose cells do have a nucleus are called eukaryotes. Most prokaryotes are unicellular organisms, although a few such as myxobacteria have multicellular stages in their life cycles or create large colonies like cyanobacteria. The word prokaryote comes from the Greek πρό- (pro-) "before" and καρυόν (karyon) "nut or kernel". Prokaryotes do not have a nucleus, mitochondria, or any other membrane-bound organelles. In other words, all their intracellular water-soluble components (proteins, DNA and metabolites) are located together in the same area enclosed by cell membrane, rather than separated in different cellular compartments.
The division to prokaryotes and eukaryotes reflects two distinct levels of cellular organization rather than biological classification of species. Prokaryotes include two major classification domains: the bacteria and the archaea. Archaea were recognized as a domain of life in 1990. These organisms were originally thought to live only in inhospitable conditions such as extremes of temperature, pH, and radiation but have since been found in all types of habitats.
Contents
1 Relationship to eukaryotes
2 Sociality
3 Reproduction
4 Structure ( Prokaryote Structure )
5 Morphology of prokaryotic cells
6 Evolution of prokaryotes
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