How do bacteria differ from other single-celled organisms?

Bacteria are placed in Kingdom Monera. They are prokaryotes while the Kindom of Protista are eukaryotic single celled organisms.


Only the bacteria can fix gaseous nitrogen. This is done by actinomycetes and rhizobacteria in a process called nitrification.


Bacteria are what allow all organisms to digest cellulose or plant fiber. Bacteria produce digestion enzymes that can degrade plant made structural molecules that higher organisms don't produce. Instead herbivores provide space for the bacteria to carry out their digestion reducing the plant's cell walls to component saccharides.

How do bacteria differ from other single-celled organisms?
For starters: They have no nucleus and no organelles (like mitochondria or ribosomes).