The thinnest of the three components of the cytoskeleton

Fibers with diameters in a middle range

Provide mechanical stability and resistance to shear stress

**************************** determine the positions of membranous organelles and direct intracellular transport

**************************** determine the shape of the cell’s surface and are necessary for whole-cell locomotion

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Hollow, cylindrical structure of polymerized α- and β-tubulin dimers with polarized ends

Helical structure of strands of polymerized actin subunits with polarized ends

Made from strands of anti-parallel tetramers, which are composed of a variety of proteins (e.g., vimentin, desmin, keratin, neurofilament, glial fibrillary acid proteins) depending on the specific cell

Involved in maintenance of cell structure.

Because they are not polarized, they are not involved with cellular transport

Motor proteins (*******. ********) bind to the microtubule and use ATP to transport vesicles around the cell

Found in mitotic spindles, cilia, flagella, and axons

Involved in cell motility, maintenance of cell shape, cytokinesis as well as muscle contraction

A member of the family of motor proteins that move along microtubules by walking toward the minus end.

A motor protein that moves along microtubules by walking toward the plus end

The most diverse intermediate filament family, with about 20 types found in human epithelial cells and 10 more specific to hair and nails

Type of anchoring junction that links the intermediate filaments in two adjoining cells

Main type of occluding junction in vertebrates; it seals adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other.

Anchoring junction that connects actin filaments in one cell to those in the next cell

They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.