CYTOSKELETON IN EUKARYOTES

 CYTOSKELETON

·       The Cytoplasm is the substance in which various Cellular components are found.

·       The term Cytosol refers to the fluid portion of Cytoplasm.

·      A major difference between Eukaryotic and Prokaryotic cytoplasm is that Eukaryotic cytoplasm has a complex internal structure, consisting of exceedingly Small rods (Microfilaments and Intermediate filaments) and Cylinders (Microtubules). Together, they form the Cytoskeleton.

·    Microfilaments or Actin filaments are smaller, about 7 nm in diameter, and are polymers of two intertwined strands of the protein Actin. Microfilaments function in

ü  Maintaining or changing cell shape

ü  Cell motility by cells that move by amoeboid movement, and during cell division.

·     Intermediate filaments are role like structures made up of fibrous Keratin proteins that form into fibers 8 – 12 nm in diameter. Their name comes from their intermediate size between Actin filaments and Microtubule. Its functions are

ü  Maintaining cell shape

ü  Positioning organelles in the cell.

·       Microtubules are long and hollow tubes about 25 nm in diameter containing a hollow core and are composed of the proteins α-Tubulin and β-Tubulin. Microtubules have many functions including

ü  Maintaining cell shape

ü  Maintaining cell motility by Cilia and Flagella

ü  Moving Chromosomes during Mitosis

ü  Movement of organelles within the cell.

·       Cytoskeleton also assists in transporting substances through the cell.

·    The movement of Eukaryotic cytoplasm from one part of the cell to another, which helps distribute nutrients and move the cell over a surface, is called Cytoplasmic streaming.