How Do Dinoflagellates Move?

Dinoflagellates move in a forward spiraling motion powered by the coordinated beating of two different flagella that project from the organism's body. One flagellum protrudes straight out from the back end and the other circles around the middle of the cell.

The flagellum that winds around the middle of a dinoflagellate is called the transverse flagellum, and it sits in a groove along the protist's surface called the cingulum. The transverse flagellum has a flattened appearance, and only the outer edges beat. The wave motion travels from the flagellum's base to the tip. The movement of the transverse flagellum propels the dinoflagellum forward and also facilitates turning.

The posterior flagellum, or longitudinal flagellum, begins in the cell membrane, stretches down a groove toward the back of the organism and extends out behind the dinoflagellate's body. This flagellum beats slowly and regularly to push the organism forward.

The beating motion of the flagella on a dinoflagellate is made possible by the microtubule structure inside each flagellum. The microtubules are arranged in a tube of nine pairs with two singlets situated in the center of the tube. Movement is initiated when the outer microtubule doublets slide against each other, and this movement is powered by ATP.