The negative end inside an animal cell is usually found within a region given by MTOC where MTOC stands for the microtubule organizing center. And within our eukaryotic animal cells this is known as our centrosome. So it's the centrosome region that contains our centrioles. So essentially our microtubules are made within our centrosome. Now, if the centrosome is responsible for a cell division that implies that the microtubules are also involved in cell division and that's exactly right. One function of our microtubule is to basically separate our chromosomes during cell division.