Microtubules are long thin structures that consist of the protein tubulin and typically have a diameter of about 25 nm. Characteristics of microtubules that are important for their functions include:
Long rigid shape - which enables microtubules to support other structures within the cell
Ability to generate movement - both within cells (see their role in moving centrioles during mitosis - below) and of the whole cells themselves (in the cases of microtubules that form structures such as cilia and flagella).
