What is the function of flagella in one-celled organisms?

Flagella serve primarily as a means of locomotion for one-celled organisms. These slender, whip-like structures extend from the cell body and propel the organism through its aquatic environment. By rotating or whipping in a coordinated manner, flagella enable the organism to swim and navigate toward favorable conditions, such as areas with more nutrients or optimal light.

While respiration occurs in all living cells through metabolic processes, and nutrient absorption and reproduction are essential functions, these do not encapsulate the primary role of flagella. The structure is specifically designed for movement, making locomotion its key function in one-celled organisms.