Microtubules (Tubulin Filaments)

What are microtubules made of?

Tubulin dimers composed of α-tubulin and β-tubulin.

What is the structure of a microtubule?

A hollow tube made of 13 protofilaments arranged in a circle.

How do microtubules form?

Tubulin dimers polymerize at the plus end from a microtubule organizing center (MTOC), such as the centrosome.

What is dynamic instability?

A process where microtubules constantly grow and shrink by adding or losing tubulin subunits.

What are the main functions of microtubules?

They form tracks for intracellular transport, organize organelles, and make up cilia, flagella, and the mitotic spindle.

What motor proteins move along microtubules?

Kinesin (moves toward the plus end) and dynein (moves toward the minus end).