They move vesicles, granules, organelles like mitochondria, and chromosomes via special attachment proteins. They also serve a cytoskeletal role. Structurally, they are linear polymers of tubulin which is a globular protein. These linear polymers are called protofilaments. The figure to the left shows a three dimensional view of a microtubule. The tubulin molecules are the bead like structures. They form heterodimers of alpha and beta tubulin. A protofilament is a linear row of tubulin dimers.
there are many different parts in a cell but here are the main ones: nucleus controls the cell and has all the cells DNA in it. nuclear membrane controls what goes in/out of the nucleus. mitochondria take glucose (C6H12O6) and turns it into ATP (Adenosine Triphosphate) which gives energy to the cell. endoplasmic reticulum (E.R) makes vessicles like peroxisomes and it also makes the cell bigger/smaller. Golgi apparatus creates vessicles like lysosomes and defensins to protect the cell and recycle large organelles like mitochondria. the centrisome organises the cells cytoskeleton, which is a collection of cellular 'bones' that helps the cell pseudopod, which is the cells way of moving around.