Observing microbes under the high magnification of a microscope will reveal movement in some organisms. The movement of structures within the cells is called streaming or cyclosis. Microbes that move in their environment are called motile and possess pseudopodia, cilia, or flagella. The easiest structure to observe is perhaps the flagellum (plural = flagella) which is a long whip-like strand of contractile protein material. Flagella may be located on the ends of a cell (polar) or on all sides of the cell (peritrichous). Microbes lacking a structure for movement from one location to another depend on a host to move the microbe or may remain attached to the first location. These nonmotile organisms are called sessile or attached.