In order to do so, they rotate their flagella counterclockwise (CCW), causing the flagella to bundle together to propel the cell in one direction, a phase called running. After a while, the cell rotates some of its flagella clockwise (CW), resulting in a disruption of linear motion called tumbling. read more
The hook: Many bacteria also use appendages called pilli to move along a surface. These pilli, which can cover the surface of a bacterium like tiny hairs, bind receptors and pull a bacterium forward when retracted. read more