Cytoskeleton
சைட்டோஸ்கெலட்டன்
A cell is not a fluid-filled balloon; it is a structural masterpiece. If the cytoskeleton fails, the cell collapses or loses its polarity. Do not confuse this with the cell wall; one provides rigidity, the other provides dynamic architecture.
The idea
The cytoskeleton is an elaborate network of filamentous proteinaceous structures present in the cytoplasm. It consists of three primary components: microtubules, microfilaments, and intermediate filaments. These structures are essential for providing mechanical support, maintaining the characteristic shape of the cell, and facilitating intracellular motility.
Why it matters
It provides the necessary structural integrity and internal organization required for a cell to maintain its shape and move.
NEET lens
NEET focuses on the functional triad: mechanical support, motility, and shape maintenance. Remember that these are proteinaceous structures, not organelles. Do not mistake the cytoskeleton for the endomembrane system; they are distinct functional units.
Clinical significance
Defects in cytoskeletal proteins lead to severe pathologies like muscular dystrophy or neurodegenerative disorders. For instance, mutations in dystrophin protein disrupt the connection between the cytoskeleton and the extracellular matrix, causing muscle fiber degeneration.
Introduction
Cytoskeleton is a dynamic network of protein filaments in the cytoplasm providing structural support, enabling cell movement, and facilitating intracellular transport.
Core concept
Three main types: Microfilaments (actin, 7nm) — cell shape, muscle contraction, cytokinesis, phagocytosis. Intermediate filaments (vimentin, desmin, keratin, 10nm) — structural support, nuclear scaffold. Microtubules (tubulin α+β, 25nm) — cell division (spindle), organelle transport, cilia/flagella, cell shape.
Go deeper
Microtubules are dynamic: grow from MTOC (centrosome in animal cells, other sites in plant cells). Dynamic instability — rapid growth and catastrophic shrinkage. This dynamic property is essential for mitotic spindle formation.
From Class 10
Just as bones give your body structure, cells have an internal skeleton. This is the cytoskeleton.