Microorganisms and all other living organisms are classified as prokaryotes or eukaryotes. Prokaryotes and eukaryotes are distinguished on the basis of their cellular characteristics. For example, prokaryotic cells lack a nucleus and other membrane‐bound structures known as organelles, while eukaryotic cells have both a nucleus and organelles. Prokaryotic and eukaryotic cells are similar in several ways. Both types of cells are enclosed by cell membranes (plasma membranes), and both use DNA for their genetic information.
<u>Prokaryotes</u> include several kinds of microorganisms, such as bacteria and cyanobacteria. <u>Eukaryotes</u> include such microorganisms as fungi, protozoa, and simple algae. <u>Viruses</u> are considered neither prokaryotes nor eukaryotes because they lack the characteristics of living things, except the ability to replicate (which they accomplish only in living cells). Viruses - Corona virus, HIV.
Like a prokaryotic cell, a eukaryotic cell has a plasma membrane, cytoplasm, and ribosomes, but a eukaryotic cell is typically larger than a prokaryotic cell, has a true nucleus (meaning its DNA is surrounded by a membrane), and has other membrane-bound organelles that allow for compartmentalization of functions.
