Prokaryotic and Eukaryotic Cells

Take a moment and look at yourself. How many organisms do you see? Your first thought might be that there's just one: yourself. However, if you were to look closer, at the surface of your skin or inside your digestive tract, you would see that there are actually many organisms living there. That’s right! You are home to around 100 trillion bacterial cells, which outnumber your own human cells by about 10 to one.

This means that your body is actually an ecosystem. It also means that you—for some definition of the word you—actually consist of both of the

major types of cells: prokaryotic and eukaryotic.

All cells fall into one of these two broad categories. Only the single-celled organisms of the domains Bacteria and Archaea are classified as prokaryotes—pro means before and kary means nucleus. Animals, plants, fungi, and protists are all eukaryotes—eu means true—and are made up of eukaryotic cells. Often, though—as in the case of we humans—there are some prokaryotic friends hanging around.