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6.2.2. Prokaryotic cells

Prokaryotic cells

The prokaryotic or prokaryotes are unicellular organisms which form the kingdom of moneras consisting of bacteria, algae cyanobacteria and mycoplasmas.

Prokaryotes have circular DNA as their genetic material associated with proteins other than histones . DNA is normally located in the center of the cell forming the nucleoid, since they do not have a true nucleus isolated by a nuclear membrane.

The cytoplasm of prokaryotic cells does not contain membranous organelles. It does have ribosomes, but different from those of eukaryotic cells. Instead, they have mesosomes, invaginations into the plasma membrane that contain multienzymatic assemblages that intervene in the metabolic reactions necessary for the organism to be aerobic, anaerobic, photosynthetic or chemosynthetic, in addition to intervening in cell division.

They can also have flagellainclusions (without a membrane that surrounds it) of lipids or other substances.

Bacteria also have a cell wall made up of peptidoglycans that delimits and protects the cell.

On the outside of the cell wall, it may have a capsule of a carbohydrate nature called a glucocalyx.


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Biology and Geology teaching materials for Compulsory Secondary Education (ESO) and Baccalaureate students.