Final answer:
Intermediate filaments consist of an N-terminal head and a C-terminal tail that flank a coiled rod domain. They provide tension resistance and structural support within cells and are comprised of proteins like keratin and lamins. Their unique properties allow cells to maintain shape and protect internal organelles.
Step-by-step explanation:
Intermediate filaments are elongated fibrous proteins with an N-terminal globular head region and a C-terminal globular tail region; these regions flank the elongated rod domain. The structure of intermediate filaments includes a pair of monomers that associate to form dimers.
These dimers then aggregate further to form tetramers and larger filament bundles, providing structural support within the cell. The cytoskeleton elements known as intermediate filaments get their name because their diameter, typically 8 to 10 nm, is between those of microfilaments and microtubules. Their main function is to bear tension, maintaining the shape of the cell, and anchoring organelles in place, including the nucleus.
Intermediate filaments are notable for their ability to stretch, thanks to the coiled rod regions, reminiscent of titin molecules in muscle cells. They don't have enzymatic activity and are involved in maintaining cell shape and structure. Types of proteins found in intermediate filaments include keratin, which strengthens hair, nails, and skin, and lamins, which constitute the nuclear lamina.
Intermediate filaments are distinct from other cytoskeletal elements, such as actin filaments, which resist compression, and intermediate filaments, which resist the tensional forces that pull apart cells. They are involved in different cellular structures like desmosomes and play critical roles in areas like division and muscle contraction in animals.