Prokaryotic cells lack a nucleus and other membrane-bound organelles, such as mitochondria, Golgi apparatus, endoplasmic reticulum, and lysosomes.

Here's a breakdown:

* Nucleus: This is where the genetic material (DNA) is stored in eukaryotic cells. Prokaryotes have a single circular chromosome located in a region called the nucleoid, but it's not enclosed within a membrane.

* Membrane-bound organelles: These are specialized structures within eukaryotic cells that perform specific functions. Prokaryotes lack these specialized compartments and their functions are carried out by the plasma membrane and cytoplasm.

So, while prokaryotes have some cellular structures in common with eukaryotes, their lack of a nucleus and membrane-bound organelles is a defining characteristic.