It gives the cell the ability to move inside the fluid environment in which that cell is found in. Now, although both eukaryotic and prokaryotic cells contain Flagella, and they serve the same exact purpose, the actual structure, the composition, and the mechanism by which our Flagella functions in the two types of cells differs. And this is what we're going to examine in this lecture. We're going to discuss the structure, the composition, and the mechanism by which prokaryotic Flagella works. And then we're going to compare that to eukaryotic Flagella. So let's begin with the prokaryotic case.