What is a key characteristic of prokaryotes?

Prokaryotes are defined by several distinct characteristics, one of the most crucial being that they lack a nucleus. This means that their genetic material, typically in the form of a single circular DNA molecule, is not enclosed within a membrane-bound nucleus, as is found in eukaryotic cells. Instead, the DNA is located in a region of the cell called the nucleoid. This fundamental difference distinguishes prokaryotic cells, such as bacteria and archaea, from eukaryotic cells, which have a more complex structure with organelles, including a defined nucleus.

The absence of a nucleus also implies that prokaryotic cells have simpler organizational structures and information processing mechanisms compared to eukaryotic cells. This characteristic is essential for the classification of cells into prokaryotes and eukaryotes, aiding in understanding the basics of cellular biology and organismal complexity.