Which structure is characteristic of prokaryotic cells?

Prokaryotic cells are characterized by the presence of a nucleoid, which is an irregularly shaped region within the cell where the genetic material, usually in the form of a single circular chromosome, resides. Unlike eukaryotic cells, prokaryotic cells lack a membrane-bound nucleus; instead, their genetic material is not enclosed within a nuclear envelope and is located in the nucleoid region. This distinction is fundamental to understanding prokaryotic cell structure.

In addition to the nucleoid, prokaryotic cells do contain ribosomes, which are essential for protein synthesis. However, ribosomes are also present in eukaryotic cells and do not distinguish prokaryotes from eukaryotes. The Golgi apparatus and nucleus, on the other hand, are specific to eukaryotic cells. Thus, identifying the nucleoid emphasizes the unique structural aspect of prokaryotic cells.