Question

Discuss the main types of cytoskeletal fibres in eukaryotic cells and how the cytoskeleton contributes to cellular mitosis. In your response you must describe three main fibre types and explain mitosis, its phases, and the role of key cytoskeleton components/fibres only at each phase.

Answer 1

Main types of cytoskeletal fibers in eukaryotic cell are:

Microtubules -They are hollow but microscopic tubes which consists of alpha and beta tubulin and is a part of the cytoskeleton. It helps in maintaining the cellular shape and integrity and has important role in the process of cell division, movement as well as transportation of material within the cell. They are found in all the eukaryotic cells and have a length of 25nm. It is polymer of tubulin protein and helps in maintaining the cell structure and helps in intracellular transport.

Microfilaments – They are also called as actin filaments and found in all the eukaryotic cells with a diameter of around 7nm. They are present as protein filaments and are located within the cytoplasm of the cell. They consists of two actin strands and helps with wide range of functions like cell motility, maintaining the change of cell shape, mechanical stability, cytokinesis etc. it helps in muscle contraction.

Intermediate filaments – they are important cytoskeletal component found in eukaryotic cells and have an average diameter of 10nm. They help in providing structural stability and helps in supporting the cells like muscle cells. It helps in cell shape and rigidity.

Cell division is a process by which a somatic cell divides and produces two identical daughter cell from a mother cell. Phases of cell division are:

Interphase – This phase consists of G1, S and G2 phase where the cell prepares itself for the division and the DNA material duplicates during S-phase.

Mitosis – This is further divided into prophase, metaphase, anaphase and telophase. In the prophase, the chromatin condenses to form the chromosome. This is followed by breaking down of nuclear envelop in prometaphase. In the metaphase the chromosome are aligned in the middle at the equatorial plane. This is followed by anaphase where the sister chromatid separates and leads to moving of daughter chromosome to opposite end. During the telophase, the daughter chromosome are present at the opposite pole and each of it has its own nuclei.

The microtubule helps in cellular motility function and during the mitosis it helps in creating the mitotic spindle. During the cell division, the movement of chromosome takes place along the mitotic spindle. They are cytoskeletal structure that is important part of cell division which helps in separation of sister chromatid. The actin helps in process of cytokinesis through which the daughter cells separate into two identical cells after cell division. It helps in the separation of the centrosome. The intermediate filament helps in providing mechanical support to the cell after the cell division.