Here's how it works:

* Microtubules are long, hollow cylinders made of the protein tubulin. They form part of the cytoskeleton, providing structure and support to cells.

* During cell division (mitosis and meiosis), microtubules assemble into a structure called the spindle.

* The spindle fibers attach to kinetochores, specialized protein structures found on chromosomes.

* Through a combination of motor proteins and depolymerization (breaking down) of microtubules, the spindle fibers pull the chromosomes apart, ensuring that each daughter cell receives a complete set of chromosomes.

So, while microtubules are made of protein, the actual movement of chromosomes is achieved through a complex interplay between microtubule assembly and disassembly, motor proteins, and the kinetochores.