Here's a breakdown:
* Flagella are long, whip-like structures that extend from the bacterial cell.
* They are composed of a protein called flagellin.
* Bacteria can have one flagellum (monotrichous), a few flagella at one end (lophotrichous), a flagellum at each end (amphitrichous), or flagella all over their surface (peritrichous).
* Flagella rotate like propellers, driving the bacteria forward.
Other structures can also play a role in bacterial movement, but to a lesser extent:
* Pili are shorter, hair-like structures that can help bacteria attach to surfaces. Some pili can also help bacteria move by twitching or gliding.
* Capsules are slimy layers that surround some bacteria. Capsules can help bacteria move by reducing friction and allowing them to slide more easily.
However, flagella are the primary means of movement for most bacteria.
