Bacterial flagella are long, whip-like structures that enable bacteria to move. They are made of a protein called flagellin and are anchored to the bacterial cell wall and membrane. The rotation of the flagella propels the bacterium through its environment, allowing it to swim toward nutrients or away from harmful substances. There are different types of flagella arrangements, such as monotrichous (single flagellum), lophotrichous (a cluster of flagella at one end), and peritrichous (flagella distributed all around the cell). The movement of flagella is powered by a motor mechanism that uses energy from the bacterium's proton motive force.