Difference Between Microtubules & Microfilaments

Human beings are made up of millions of cells, all of which have specific functions and specializations. Each cell's structure relates to its functions; therefore, cells are not homogeneous -- each has distinct physical characteristics. However, what they do have in common is that all cells are made up of basic cellular and cytoskeleton components. The cytoskeleton comprises microtubules and microfilaments. Although similar in appearance, microtubules and microfilaments differ in other areas.

Function

• The main function of microfilaments is to provide support to the cell. Microfilaments give the cell its distinctive shape. The overall function of the cell determines the amount of microfilaments present in a cell. Microtubules, however, are required during major cellular changes such as mitosis and endocytosis. Microtubules play a big role in cellular transport. During reproduction, the tail of the sperm is composed of microtubules, which help it travel along the vaginal passage to the fallopian tubes.

Location

• Microfilaments and microtubules are both located within the cytoskeleton of the cell. The mitosis process is divided into six stages, and during the interphase stage, the microtubule will move from one end of the cell to the other and provide the cytoskeletal support needed for cell division. Microfilaments tend to stay at the outermost part of the inner cell and close to the plasma membrane. Their location helps them provide necessary and immediate action when the plasma membrane experiences disturbances.

Size

• Microfliaments look like woven mesh rods that can bend and curve along with the cell. Microfilaments are extremely thin, making them the thinnest filaments of the cell. Microtubules are much larger than microfilaments and have a straight and hollow rodlike appearance. Microtubules hold the cell together as it moves and travels along the body.

Protein

• Microtubules and microfilaments differ in their protein structures. Microtubules are composed of a globular protein called tubulin. The tubulin molecules are assembled in a linear fashion with alternating alpha and beta tubulin making up the microtubule. Microfilaments are composed of actin protein, particularly, F-actin protein. The sequence of the F-actin molecules determine the mesh wovens of the microfilaments.