Question

Mention the role of microtubules and microfilaments in structure and function of eukaryotic cells?? (7 marks)

Answer 1

Microtubules and Microfilament structure and function in eukaryotic cells:

Microtubules:

Structure: Microtubules are Hollow rods and fibrous in the structure which helps to shape and support the cell. The inner space of the hollow microtubule cylinders called lumen. It is composed of the protein mainly alpha and beta tubulin. Microtubules can grow as long as 50 micrometers.

Microtubules also help in the formation of the cell structure called centrioles and asters, which mainly seen in or found in animal cells. Centrioles are composed of a grouping of Microtubules arranged in a 9+3 pattern whereas asters are star-shaped in a structure which form around each pair of centrioles during cell division.

Function:

1. Cell division and Mitotic Spindle: The role of Microtubules in cell division is that it helps in the formation of the mitotic spindle which help migration of duplicated chromosomes during anaphase.

2. Movement: Microtubules help in the formation of cilia and flagellum. Cilia and flagellum help in the movement of the cell as well as in the formation of cell structure.

3.Cell Transporation: Microtubules help in the transport of organelles and vesicles in the cells as motor protein use them as a track to from one part of cell to another.

Microfilament:  

Structure: Microfilament is fine, thread-like protein fibers. It is also known as actin filaments. It is made up of actin subunits (G-actin) and has a diameter of 6-8 nanometers.

Globular actin is the monomer of the globular protein of 375 amino acid. Microfilaments are flexible and strong.  

Function: Microfilament form a thin skeleton just inside the plasma membranes called the cortical cytoskeleton which provides stiffness shape and structure to the membrane.

They are responsible for the all protrusion of cells, microvilli, phagocytic protrusion.