Prokaryotic cells are cells that have organelles that lack membranes and have nucleoids instead of nuclei.
Prokaryotic cells are much smaller than eukaryotic cells. They may exist in several different shapes like rods, spheres, coccus, spirochetes, etc.
Generally, prokaryotic cells are bacteria and archaea.
a. E-coli (rod-shaped prokaryotes that reside in the lower intestine of humans and other warm-blooded organisms and may cause food poisoning and regurgitation)
b. Streptococcus (chain-like collection of unicellular organisms that reside at the back of the throat and cause sore throat and tonsillitis)
c. Soil bacteria
d. Archaea (found in acidic environments).