Thus the model uses a flagellum for propulsion purposes.

And then each of them, they can code for the proteins necessary to produce all of their extra appendages, the flagellum, which is this long tail like thing that can help it move.

I won't say primitive, because that's making a value judgment on these things, but using you know, these flagellum are on the order of several nanometers, on the order of tens of nanometers wide.