Final answer:
The defining feature of a prokaryotic cell is the lack of a membrane-bound nucleus; genetic material is located in the nucleoid region.
Step-by-step explanation:
One defining feature of a prokaryotic cell is the lack of a membrane-bound nucleus. Instead of a nucleus, the genetic material in a prokaryotic cell is found within a central part of the cell called the nucleoid. Prokaryotic cells also generally lack other membrane-bound organelles, which are typical of eukaryotic cells, such as mitochondria, the endoplasmic reticulum, and the Golgi apparatus. Instead, they have a simple structure with a single chromosome made of circular DNA located in the nucleoid region.