Prokaryotic cells are the primitive unicellular cells found on earth.
They lack a well-defined nucleus and organelles.
They are capable of performing all the functions of life such as respiration, digestion, circulation, etc.
Prokaryotes lack compartmentalization in the cell. Cellular compartments are absent in prokaryotes, although they perform functionalities as multicellular entities.
They are the most basic organisms present and hence, are unicellular.