Attracting Abundance

- 101 -

The Law

Belief - XIII

Our Cellular Biology - XII

We will learn about cytoskeleton.

The cytoskeleton is a kind of scaffolding present in all cells. It is made of proteins.

It keeps cell shape, protects the cell and enables cells to move. It helps transport inside the cytoplasm (the movement of organelles, for example), and in cell division. 

Eukaryote cells contain three main kinds of cytoskeletal filaments, which are microfilaments, intermediate filaments, and microtubules. They give the cell structure and shape. Cytoskeletal elements interact closely and often with the cell membrane and endoplasmic reticulum. 

Microfilaments, or actin filaments, are the thinnest filaments of the cytoskeleton and are found in the cytoplasm of eukaryotic cells. The polymers of these linear filaments are flexible but still strong, resisting crushing and buckling while providing support to the cell.

Microfilaments are very versatile cell components that serve a role in cytokinesis, movement, and changes in cell shape. The strong but flexible arrangement of the microfilaments' framework allows it to help with cell movement.

Note: Cytokinesis is the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells.

To make a cell move, one end of the actin filament stretches out while the other end pulls itself in tighter. The process repeats until movement is complete. 

Microfilaments also serve an important role in the muscle movement.  

Intermediate filaments (IFs) are a type of cytoskeletal fiber found in eukaryotic cells. 

In some cells, there are as many as ten times the number of intermediate filaments as there are other microfilaments or microtubules. This abundance of IFs means they serve several important roles in the cell.

Intermediate filaments are usually strong and ropelike. Their job is mainly structural, providing strength and support for the more fragile tubulin structures.

All cells have intermediate filaments, and some cells have several different types. Some intermediate filaments are closely linked to specific cell types. Neurofilaments, as the name suggest, are found exclusively in neurons. Muscle cells contain a type called desmin filaments. Other types of intermediate filaments are found more widely distributed in various types of cells. 

The function of intermediate filaments is largely mechanical, meaning they provide support for the cell so that other microfilaments can more readily do their transport jobs. Some intermediate filaments are even arranged in a mesh-like pattern to provide for the different support needs of different kinds of cells.

Microtubules are hollow, fibrous shafts whose main function is to help support and give shape to the cell. They also serve a transportation function, as they are the routes upon which organelles move through the cell. They are most often found in all eukaryotic cells and, together with the microfilaments and intermediate filaments, form the cytoskeleton.

Microtubules have many more jobs than just giving support to the cell. The microtubules also play a very important role during cell division. Their primary cell division function is to connect to the chromosomes, help those chromosomes complete their first split, and then move the new chromosomes to their places in the new daughter cells. This job is carried out by microtubules that make up the centrioles, organelles that have been given the specific job of helping cells divide. After cell division has finished, those same microtubules return to their functions in other parts of the cell.

Other than support, organelle movement, and cell division, microtubules also play a part in forming large structures on the outside of the cells. Microtubules can combine in very specific bundles to facilitate cell movement. 

Should you want to understand the cytoskeleton structure in greater detail, the video will be helpful:

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Prabir