Prokaryotic cells are simple, single-celled organisms that lack a nucleus and other membrane-bound organelles. They are typically smaller than eukaryotic cells and have a more basic structure. The genetic material in prokaryotic cells is found in a region called the nucleoid, and they reproduce asexually through a process called binary fission. These cells are classified into two main groups: bacteria and archaea. Prokaryotic cells have a cell wall that provides structure and protection, and they can be found in various environments, from soil to extreme conditions like hot springs. Their simplicity allows them to adapt quickly to changing environments.