The shape and function of these cells are completely dependent on the fibers and filaments that criss-cross the cytoplasm. Three types of filaments make up the cytoskeleton. Their identity and importance became apparent after electron microscopists recognized how dominant a feature of the cytoplasm they were.
Polymers usually form a two strand structure, known as a thin filament.
Microfilaments can be a part of very stable structures as well as very dynamic cellular events. All cells depend on actin to assist cell division, particularly the cleavage event that separates the cell cytoplasm after chromosomal separaton. Thin filaments, on the other hand, can only be visualized by transmission electron microscopy. They first make small polymers which 'seed' the production of longer filaments. Let's consider that T cell that kills a macrophage infected with virus.