Prokaryotic cells comprise bacteria and archaea. They typically have a diameter of 0.1–5 μm, and their DNA is not contained within a nucleus. Instead, their DNA is circular and can be found in a region called the nucleoid, which floats in the cytoplasm. Prokaryotes are organisms that consist of a single prokaryotic cell.
Eukaryotic cells are found in plants, animals, fungi, and protists. They range from 10–100 μm in diameter, and their DNA is contained within a membrane-bound nucleus. Eukaryotes are organisms containing eukaryotic cells.