What is the main difference between prokaryotic and eukaryotic cells?

The primary distinction between prokaryotic and eukaryotic cells lies in the presence of a nucleus. Prokaryotic cells, such as bacteria, do not possess a defined nucleus; instead, their genetic material is found in a region called the nucleoid, which is not enclosed by a membrane. This absence of a nucleus is a fundamental characteristic of prokaryotes. In contrast, eukaryotic cells, which include plants, animals, fungi, and protists, have a well-defined nucleus that houses their DNA. This structural difference is significant because it reflects evolutionary adaptations and complexities: eukaryotic cells often have more intricate organization and compartmentalization, which allows for greater functional specialization.

Understanding this distinction is crucial for grasping basic cellular biology, as it affects not only cell structure but also how these cells reproduce and interact with their environments.