Tsütoskeleton

The cytoskeleton is a dynamic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and internal organization. It is composed of three main types of filaments: actin filaments (microfilaments), intermediate filaments, and microtubules. These filaments are constantly being assembled and disassembled in response to the cell's needs.

Actin filaments are the thinnest of the cytoskeletal elements and are primarily involved in cell movement, muscle contraction, and cytokinesis (the division of the cytoplasm during cell division). They are polymers of actin protein monomers. Intermediate filaments are rope-like structures that provide mechanical strength and maintain cell shape, resisting mechanical stress. They are composed of various protein subunits, depending on the cell type. Microtubules are the thickest of the cytoskeletal elements and are hollow tubes made of tubulin protein. They play crucial roles in intracellular transport, cell division (forming the spindle fibers), and the formation of cilia and flagella.

The cytoskeleton is essential for a wide range of cellular processes. It provides structural support to the cell, enabling it to maintain its shape and resist deformation. It is also involved in cell motility, allowing cells to move through their environment or to change shape. Furthermore, the cytoskeleton serves as a scaffold for the organization of organelles within the cell and facilitates the transport of molecules and vesicles between different cellular compartments. It is a fundamental component of eukaryotic cell structure and function.