- Mechanical support for shape of cell (esp. animal cells).
- Support and locators for organelles and macromolecules in cell.
- Movement of entire cell.
- Endocytosis, exocytosis, pinocytosis.
- Movement of organelles and vesicles along "monorails".
Three groupings of cytoskeleton components are recognized; microtubules, microfilaments, intermediate filaments.
- Structure - straight, hollow rods of globular proteins.
- Up to 25 µm long. 25 nm in diameter.
- Function - shape, support, organelle monorails.
- Very consistent structure across all eukaryotes.
- Structure - solid rods of globular proteins 7nm in diameter.
- Function - support and muscles (1000's in parallel).
- Diverse group with a variety of structures and composition.
- May be more permanent than the microtubules and microfilaments.
- Thought to anchor the nucleus.
Cilia and flagella
- Specialized arrangement of microtubules.
- Common structure - 9 pairs of microfilaments surround two pair in middle (9 + 2).
- Cilia structure - numerous and small (0.25 µm dia, up to 20 µm long).
- Cilia function - undulating waves move mucous layer of lungs.
- Flagella structure - one or two per cell and long (up to 200 µm).
- Flagella function - movement through a very viscous medium.