Final answer:
Cytoskeletal filaments are not formed from protein monomers held together by covalent bonds. They are actually held together by non-covalent bonds, specifically protein-protein interactions.
Step-by-step explanation:
Cytoskeletal filaments are not formed from protein monomers held together by covalent bonds. This statement is false.
Microtubules are composed of alpha and beta tubulin protein monomers. Monomeric actin proteins make up microfilaments. Intermediate filament proteins, on the other hand, are made up of long fibrous subunits of a protein called keratin. These filaments are wound together like the threads that compose a rope. Therefore, cytoskeletal filaments are formed from protein monomers held together by non-covalent bonds.