What structure enable bacteria and protozoa to move?
Protozoa have several ways of moving, depending on the type of protozoa. Amoebas move via amoeboid locomotion; they extend a pseudopodia outward from the amoeba cell. The pseudopodia attaches to the surface beneath the amoeba. By a flowing motion of the cytoplasm within the cell and the pseudopodia, the whole cell will move forward. Protozoa that are categorized as as flagellates move forward with a flagellum. Some protozoa have only one flagellum, which looks like a small whip, and some have hundreds. Paramecium are ciliates: they use cilia, hair-like structures that guide and direct movement. Cilia are shorter than flagella. Some bacteria have flagellum, however many do not. The bacteria that are not self-propellant will be moved along with the current of the fluid they are in. Some bacteria excrete a lubricating substance that allows them to glide along easier and attach themselves to the host (this is called a glycocalyx). I hope that helps.