Hi, I'm Jim Shields for About.com, and today I'm going to teach you about prokaryotic cells. A prokaryotic cell, unlike a eukaryotic cell, lacks a nucleus. Simple life forms like bacteria are examples of prokaryotes. In this diagram of a prokaryotic cell, you can see that there is no nucleus, but that the DNA is loosely organized in one area of the cell called the nucleoid, which doesn't have a distinct membrane to contain the DNA. The absence of a nucleus and simpler genetic martial allows prokaryotic cells to reproduce faster, as much as 10 times faster, than eukaryotic cells. Prokaryotic cells were earth's first life forms, existing for millions of years before the more complex eukaryotic cells were developed. An interesting fact is that there actually are ten times more prokaryotic cells in the form of bacteria in the human body, than there are eukaryotic cells. Thanks for watching. To learn more about biology, visit us on the web at About.com.