Microtubules are the largest type of filament, with a diameter of about 25 nanometers (nm), and they are composed of a protein called tubulin. Actin filaments are the smallest type, with a ...

It consists of a pair of centrioles — structures analogous to the basal bodies of cilia and flagella — surrounded by pericentriolar material from which microtubules are nucleated and anchored.

This is a picture of Drosophila melanogaster (fruit fly) sperm, showing the growing flagella (in green). The structure at the base of flagella is shown in red, and blue marks the DNA of each sperm ...