flagellae

• like cilia but longer
• stick out from the cell surface and are surrounded by the plasma membrane
• have a outermsmbrane and a ring of nine pairs of protein microtubules inside with a pair of microtubules in the middle
• used primarily to enable cells motility
• in some cells they are used as a sensory organelle detecting chemical changes in the cells environment
• the microtubules contract to make it move
• they are used on cells to propel forward