Which answer most accurately summarizes the (1) structural and (2) functional properties of actin filaments, intermediate filaments, or microtubules?.

Actin filaments:

(a) one subunit type;

(b) one cellular role

Intermediate filaments:

(a) many subunit types;

(b) one cellular role

Microtubules:

(a) two subunit types;

(b) one cellular role

Intermediate filaments:

(a) many subunit types;

(b) diverse cellular roles

Actin filament are one subunit type.

Intermediate filament has many subunit types.

Microtubules has two subunit types.

Intermediate filament has diverse cellular role.

Explanation:

Actin filament is a monomeric subunit of two types of filament in cells. The two types of filaments are the microfilaments which is one of the three components of the cytoskeleton and the thin filament which is a part of the contractile apparatus in muscle cells. Actin filaments are made up of identical actin protein arranged in a long spiral chain. Actin filaments play a major role in cytokinesis and in cell movement.

Intermediate filament have a strong and rope-like structure. Intermediate filaments are composed of various proteins, depending on the type of cells they are found. The play a significant role by working in tandem with microtubules to provide strength and support do flagile tubule structures.

Microtubules contains two polypeptide subunits in which the dimers of this subunits string together to form long strands called the protofilament. They are long and cylindrical in structure. They perform a variety of functions which include the determination of cell shape, involvement in cell movement and in the position of organelles in cells.