So now that we've talked about some features of prokaryotic cells in our last lesson video, in this video we're going to talk about some features of Eukaryotic Cells. Now, Eukaryotic Cells, unlike prokaryotic cells, actually contain several membrane-bound organelles, including a nucleus. Eukaryotic cells have a nucleus, unlike prokaryotic cells that do not have a nucleus. Eukaryotic DNA is actually linear in its shape, unlike prokaryotic DNA, which is circular in shape. Eukaryotic DNA is found inside of the nucleus it contains. Whereas prokaryotic cells do not have a nucleus, so their DNA is not found inside of a nucleus. Instead, recall that prokaryotic cells, their DNA is found inside of the nucleoid. So, don't confuse the nucleus with the nucleoid.
Also, recall from our last lesson video that all cells have structures called ribosomes that make proteins. We'll talk more about ribosomes later in our course, but we know all cells have ribosomes. Recall from our last lesson, prokaryotic cells have really small 70S ribosomes. But eukaryotic cells, or eukaryotes, have large ribosomes that we call 80S ribosomes, and they are larger.
Eukaryotic cells, instead of dividing by binary fission like prokaryotic cells, divide by a process called mitosis and cytokinesis. We'll talk more about mitosis and cytokinesis later in our course. Eukaryotic cells divide by this more complicated process. If we take a look at our image of a eukaryotic cell, notice the many membrane-bound organelles inside the eukaryotic cells; there's a lot more going on inside a eukaryotic cell than a prokaryotic cell. Eukaryotic cells are much larger and can fit many more organelles.
Notice that eukaryotic cells have a nucleus, represented by the circle you see here. Inside the nucleus, you'll find the cell's DNA, which is linear. And these little blue circles throughout represent ribosomes. Zooming into one of these blue circles, it represents a eukaryotic ribosome, which is quite large, and is known as an 80S ribosome. The 'S' is an abbreviation for 'Svedberg unit,' a term we are not really discussing in this course.
This introduction to some of the features of eukaryotic cells concludes our lesson for now. As we move forward in our course, we'll be able to discuss more about these cells. I'll see you all in our next video.