But both types of filaments give the cell structure, they give the cell the shape and increase the tensile strength of our cell. So basically, if we try to pull on the cell what keeps the cell from being split are these types of fibers the microfiliminants and our intermediate filaments. Now, let's move on to the thickest type of filament fiber known as the micro tubules. So microtubules are the largest of the three and are rigid hollow tubes made of a protein known as tubulin. And there are two versions of tubulin. We have alpha as well as beta tubulin and together the alpha and the beta tubulin proteins which are globular proteins, they basically create a helical structure, structure that winds as shown.