Which structure aids in the locomotion of some bacteria?

The flagellum is a key structure that aids in the locomotion of some bacteria. It is a long, whip-like appendage that rotates to propel the bacterial cell through its environment. The movement generated by the flagellum allows for motility, enabling bacteria to swim toward favorable conditions, such as nutrients, or away from harmful substances.

Flagella are essential for certain species of bacteria, contributing not only to their movement but also to their ability to colonize and infect hosts, increasing their chances of survival and reproduction. This feature is particularly significant in pathogenic bacteria, where mobility can influence virulence and infection processes.

While the pilus is involved in processes like adhesion and conjugation, it does not provide motility in the same way that a flagellum does. The capsule serves a different purpose, primarily providing protection and helping with immune evasion rather than movement. Ribosomes are critical for protein synthesis but are not involved in locomotion or movement.