In this video, we're going to talk about prokaryotic and eukaryotic cells. And so, prokaryotic and eukaryotic are actually the broadest and the most distinct groupings of all life. The reason for this is because prokaryotic cells actually include two different domains of life. It includes both domain bacteria and it also includes domain Archaea as well. Both bacteria and archaea are considered prokaryotic. Prokaryotic cells specifically do not have an organelle called a nucleus, and so prokaryotic cells do not have a nucleus. Whereas, eukaryotic cells, on the other hand, these are cells that do have a nucleus along with other membrane-bound organelles as well. What you'll notice is in prokaryotic and eukaryotic, comparing the two words, they both have this karyo root, and the karyo root is referring to the kernel, and it's referring to the kernel of the cell, which is the nucleus. Karyo is referring to the nucleus, and both, the karyo root is found in both of these words. So both of them are referring to the nucleus. And really what's different are the roots here pro and eu as we, kind of highlighted above. Pro and eu is what makes these two words different from each other. So we focus on these roots, so we can better understand the meaning of prokaryotic and eukaryotic. And so pro is a root that means before. And so if you put it together, you get pro or before the, kernel or the nucleus, so before the nucleus. Before the nucleus is pretty much referring to not having the nucleus because it's before the nucleus. The eu prefix actually means good. And so, putting this together with the karyote, you get good nucleus, and that means that it does have a good nucleus or just the nucleus. And so hopefully that can help you distinguish between prokaryotic and eukaryotic a little bit better. So down below, we're gonna take a look at this table here of prokaryotic and eukaryotic cells.
So, notice that the table has these column headers that are the domains of life, the cell type, the nucleus, organelles, cell size, and cellularity. And so, of course, for the domains of life, we know that there are three domains of life. There are, domain bacteria, domain archaea, and domain eukarya. Now both bacteria and archaea are, collectively, going to be the same cell type of prokaryotic. And this is because, in terms of the nucleus, both bacteria and archaea, they do not have a nucleus, which means that the nucleus is absent. Now on the other hand, of course, Eukarya are going to be eukaryotic cells, and eukaryotic cells specifically do have a nucleus. So here we can say that the nucleus is present. Now in terms of other membrane-bound organelles, prokaryotic cells, including bacteria and archaea, they do not have membrane-bound organelles, so they will be both, absent here. But, of course, in eukaryotic cells, organelles are going to be present. And moving forward in our course, we'll talk about a lot of these different types of organelles found in eukaryotic cells.
Once again, in terms of cell size, it's really important to note that prokaryotic cells are significantly smaller than eukaryotic cells, which are significantly larger. And so you can see here that, prokaryotic cells, they can range in size, of course, but they're going to be about 1 micrometer here in diameter. Whereas, eukaryotic cells, which can also range in their sizes, are going to be much larger on average. So here we have a 100 micrometers. So you can see, that eukaryotic cells can be, up to a 100 times larger than prokaryotic cells in some cases. Now in terms of cellularity, it's important to note that prokaryotic cells, including bacteria and archaea, are actually unicellular, meaning that they're only made up of one single cell since uni means one or singular. Whereas, of course, eukaryotic cells, they can either be unicellular or single-celled or they can be multicellular. And so the multicellular organisms that you're aware of are all going to be eukaryotic, and this is, of course, where humans fall. Humans are multicellular. And so this here, concludes our introduction to prokaryotic and eukaryotic cells and we'll be able to continue to talk more and more about the differences between the two as we move forward in our course. So I'll see you all in our next video.