What are the types of unicellular organisms?

The two types of unicellular organisms are classified as prokaryotes and eukaryotes. Within these types, different kinds of unicellular organisms exist. All prokaryotes lack a nucleus, and possess a cell wall composed of peptidoglycan. They also have fimbriae for attachment to host cells and use pili for genetic material exchange. Archaebacteria and eubacteria are examples of unicellular organisms in prokaryotes. In contrast to prokaryotes, all eukaryotes have a membrane-bound nucleus and are larger in size than prokaryotes. The nucleus of eukaryotic cells contain their genetic information. Protisa and protozoa are a few examples of unicellular organisms in eukaryotes.