prokaryótar
Prokaryótar, commonly called prokaryotes, are single-celled organisms characterized by the absence of a nucleus and other membrane-bound organelles. Their genetic material is typically a single circular chromosome located in a region of the cytoplasm called the nucleoid, and they often carry smaller DNA molecules known as plasmids. Prokaryotes have ribosomes of the 70S type and a cytoplasmic membrane that lies beneath a rigid cell wall. In bacteria the cell wall commonly contains peptidoglycan, whereas archaea have different cell wall compositions, such as pseudopeptidoglycan or other polymers.
Prokaryotes are divided into two domains: Bacteria and Archaea. A traditional older framework used the kingdom
Metabolically, prokaryotes show remarkable diversity. They include photosynthetic cyanobacteria, chemolithoautotrophs, and chemoorganotrophs. Some are aerobic, others
Ecologically, prokaryotes drive nutrient cycling, decompose organic matter, fix nitrogen, and form mutualistic relationships with plants