Final answer:
Intermediate filaments are made up of long fibrous subunits of keratin. They form dimers, which aggregate to form larger filament bundles. Intermediate filaments resist tension forces, maintain cell shape and structure, and anchor organelles within a cell.
Step-by-step explanation:
Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together. The subunits have a common structure consisting of a pair of monomers that are non-polar. These monomers further aggregate to form dimers, which then form tetramers and larger filament bundles. Unlike microtubules and actin filaments, intermediate filaments can stretch due to the coiled rod regions of the filaments. This property allows them to resist tension forces and maintain cell shape and structure. Intermediate filaments also anchor organelles together within a cell and form special cell-to-cell junctions.