Microtubules, Microfilaments and Intermediate Filaments

The question also asks to compare the structure:

Microtubules- hollow cylinders composed of tubulin

Kind of unsure about MF and IF, I know
Microfilaments- composed of actin
Intermediate Filaments-

Microfilaments are two-stranded helical polymers of the protein actin. They appear as flexible structures with a diameter of 5 - 9 nm and are organized into a variety of linear bundles, two-dimensional networks, and three-dimensional gels. Although actin filaments are dispersed throughout the cell, they are most highly concentrated in the cortex, just beneath the plasma membrane. Microtubules are long, hollow cylinders made of the protein tubulin.With an outer diameter of 25 nm, they are much more rigid than actin filaments. Microtubules are long and straight and typically have one end attached to a single microtubule-organizing center (MTOC) called a centrosome.

Basically, the cytoskeleton is unique to eukaryotic cells. It is a dynamic three-dimensional structure that fills the cytoplasm. This structure acts as both muscle and skeleton, for movement and stability. The long fibers of the cytoskeleton are polymers of subunits. The primary types of fibers comprising the cytoskeleton are microfilaments, microtubules, and intermediate filaments.

Microfilaments

Microfilaments are fine, thread-like protein fibers, 3-6 nm in diameter. They are composed predominantly of a contractile protein called actin, which is the most abundant cellular protein. Microfilaments' association with the protein myosin is responsible for muscle contraction. Microfilaments can also carry out cellular movements including gliding, contraction, and cytokinesis.

Microtubules

Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin--these subunits are termed alpha and beta. Microtubules act as a scaffold to determine cell shape, and provide a set of "tracks" for cell organelles and vesicles to move on. Microtubules also form the spindle fibers for separating chromosomes during mitosis. When arranged in geometric patterns inside flagella and cilia, they are used for locomotion.

Intermediate Filaments

Intermediate filaments are about 10 nm diameter and provide tensile strength for the cell.

intermediate filaments are made up of alfa tubulin