Cytoskeleton Functions and Structure

Study Notes

A complex network of protein tracks and tubules found in the cytosol of eukaryotic cells.
Provides mechanical support, maintains three-dimensional shape, and is crucial for animal cells that lack rigid walls.

Composed of three major components: microfilaments, intermediate filaments, and microtubules.
Each component differs in protein type, diameter, and assembly into larger structures.

Molecular machines that use ATP for movement along cytoskeletal components.
Three classes include myosin, kinesin, and dynein, all aiding in organelle transportation.

Thin solid rods with a diameter of approximately 7 nanometers, constructed from actin proteins.
Have a plus and minus end and are twisted double chains of actin subunits.
Functions include:
- Providing strength against stretching and compression.
- Anchoring cells to one another and forming a network just inside the plasma membrane.
- Contributing to the structure of microvilli in nutrient-absorbing cells.
- Facilitating cell motility through interactions with myosin in muscle contraction and amoeboid movement.

Named for a diameter of 10 nanometers, larger than microfilaments.
Constructed from various protein subunits, including keratins; found in some animal cells.
Functions include:
- Supporting cell shape and anchoring organelles.
- Providing structural integrity to cells, especially in hair and nails.
- Binding some cells together through desmosomes.

Hollow rods with a diameter of 23 nanometers, made of tubulin dimers (α-tubulin and β-tubulin).
Functions include:
- Providing shape and support for the cell.
- Serving as tracks for motor proteins (kinesin and dynein) to move organelles.
- Guiding vesicle transport from the ER to Golgi apparatus and vice versa.
- Involved in chromosome separation during cell division and movement of cilia and flagella.

Extensions containing microtubules, differing in length, number, and beating patterns.
Both structures aid in locomotion for unicellular organisms and sperm.
Cilia can move fluids across cell surfaces, like in the trachea and oviduct.
Primary cilia serve as signal-receiving antennas for cells, transmitting environmental signals to trigger internal cellular responses.