 We're going to talk a little bit about prokaryotic and eukaryotic cells. Both of these words come from Latin, and the root karyos in Latin means kernel, and in biology we use that word to refer to the nucleus. So that gives us a little bit of a clue as to the differences between prokaryotic and eukaryotic cells, because pro means before, this word refers to before a nucleus, and u means true or good, this word refers to a true nucleus. So one of the major differences is that prokaryotic cells have no nucleus, and eukaryotic cells have a true nucleus. Another major difference that can be defined using the origins of the word is that pro, since it means before, prokaryotic cells are more ancient. They're ancient, they're older than eukaryotic cells, which are more contemporary. In addition to lacking a nucleus, prokaryotic cells lack many other organelles. For example, the chlorophyll that any photosynthetic prokaryotic cells use is spread throughout the cytoplasm, whereas in eukaryotic cells that chlorophyll is in chloroplasts. The DNA in eukaryotic cells is organized into chromosomes, whereas the DNA in prokaryotic cells is organized into a plasmid. It's just a circular piece of DNA. Because prokaryotic cells have no nucleus and no organelles, they're often considered simpler than eukaryotic cells, which are more complex. And they're often smaller. On average, eukaryotic cells are about 10 times larger than prokaryotic cells. These types of cells, prokaryotic cells, can be found in bacteria and archaea, whereas eukaryotic cells make up plant and animals. This should give you a background on some of the major differences between prokaryotic and eukaryotic cells.