What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells are distinguished from eukaryotic cells primarily by their lack of a nucleus. In prokaryotic cells, genetic material is not enclosed within a membrane-bound nucleus; instead, it is found in a region called the nucleoid. This simplicity is a key characteristic of prokaryotes, which include bacteria and archaea.

In contrast, eukaryotic cells possess a well-defined nucleus that houses their DNA and is surrounded by a nuclear envelope. This structural difference is foundational, as it leads to various functional differences between the two types of cells. For example, eukaryotic cells can organize their genetic material more complexly and perform more advanced cellular processes.

While the presence of mitochondria, the size differences, and the presence of chloroplasts may also serve as distinguishing features in specific contexts, they do not universally separate prokaryotic from eukaryotic cells. Mitochondria and chloroplasts are organelles found exclusively in eukaryotic cells, and size can vary greatly among both types of cells. Therefore, the absence of a nucleus remains the most definitive characteristic that sets prokaryotic cells apart from their eukaryotic counterparts.