A prokaryotic cell has no true nucleus and its organelles are not bound by any membrane. Bacteria and their anaerobic cousins, archaea, are prokaryotes. While these microorganisms are too tiny to see with the naked eye, prokaryotes fill up much of the Earth’s biomass. Without them, other forms of life would not be sustainable.
All prokaryotes are single-celled organisms. They come with internal and external structures to function properly and live.
Prokaryotic cells are encased in a cell membrane that separates its insides from the environment. Many prokaryotes also have another protective layer called a cell wall. To move around, these cells use parts such as the whip-like flagella and pili which stick to surfaces.
The interior of the cell is filled with the cytoplasm, a thick, watery fluid. Unlike eukaryotic cells, there are no organelles inside, save for the ribosomes and the nucleoid. The ribosomes are made of RNA and proteins, and act as sites that perform protein synthesis. Instead of a well-defined nucleus, the nucleoid is simply a region where bacterial chromosomes are stored.
Some prokaryotes also have vacuoles that store nutrients and help expel wastes.
The prokaroytic cell labeled diagram presented here can be an informative guide to unicellular life and help distinguish the differences between prokaryotic and eukaryotic structures.