Which type of cells lacks membrane-bound organelles?

Prokaryotic cells are defined by their lack of membrane-bound organelles, which is a primary distinction between them and eukaryotic cells. In prokaryotic cells, the genetic material is not enclosed within a nucleus; instead, it is found in a region called the nucleoid. Other cellular processes occur within the cytoplasm, which lacks the compartmentalization seen in eukaryotic cells.

Eukaryotic cells, on the other hand, contain various membrane-bound organelles, such as the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus, which allow for compartmentalized functions within the cell. Both animal and plant cells are types of eukaryotic cells, so they also possess these organelles. Therefore, the defining characteristic of prokaryotic cells is their simplicity and lack of these specialized structures, making them distinct in the biological classification of cells.