Microtubules

Microtubules are a component of the cytoskeleton in cells. They are made up of a globular protein called tubulin and are roughly 25 nm in diameter.

Microtubules have multiple functions within a cell. The rigidity of microtubules allows them to maintain the cell's shape. They also control movement of the cell as well as movement of intracellular organelles . During mitosis, microtubules form the mitotic spindle required to separate the chromosomes.