Composed predominantly of a contractile protein called actin, most abundant cellular protein. 42,000 Association with the protein myosin is responsible for muscle contraction. Microfilaments can carry out cellular movements including gliding, contraction, and cytokinesis. Microtubules Cylindrical tubes, 20-25 nm in diameter. A scaffold to determine cell shape.
Forms spindle fibers for separating chromosomes during mitosis.
Arranged in geometric patterns inside flagella and cilia, used for locomotion. Very different from bacterial flagella. EM Studies John Heuser has developed techniques for visualizing cellular fibers that involve the use of detergents to remove cell membranes and soluble proteins leaving the cytoskeleton. Cells are then rapidly frozen and prepared for the electron microscope. Heuser, J. and Kirschner, M., J. Cell.