Cell Cytoskeleton: Structure, Functions, Types & NCERT Notes

🔍 1. What is the Cytoskeleton? (Cytoskeleton PDF)

The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea.^[2] In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components: microfilaments, intermediate filaments, and microtubules, and these are all capable of rapid growth and/or disassembly depending on the cell's requirements.

🧫 2. Components of Cytoskeleton

Component Size Protein Function

Microtubules ~25 nm Tubulin Cell shape, chromosome movement, cilia & flagella

Microfilaments ~7 nm Actin Cell movement, muscle contraction, cytokinesis

Intermediate Filaments ~10 nm Keratin, vimentin, etc. Mechanical strength, cell stability

📘 Mnemonic to Remember

🧠 “MIC-MIC-IN”

MICrotubules – Largest

MICrofilaments – Smallest

INtermediate – In between

🌀 3. Functions of Cytoskeleton

🧍 Maintains cell shape and structure

🚶‍♂️ Helps in intracellular transport of organelles

🧬 Chromosome movement during cell division

✂️ Cytokinesis (division of cytoplasm)

🧭 Guides vesicle movement and organelle positioning

🔍 4. Special Roles

Component Special Function

Microtubules Spindle fibers during mitosis

Microfilaments Amoeboid movement, cleavage furrow

Intermediate Filaments Nuclear lamina formation

🧪 NEET Focus Points

✅ Microtubules = tubulin + 25 nm

✅ Microfilaments = actin + 7 nm

✅ Intermediate filaments are not involved in motility

Frequently Asked Questions (FAQs)

What is the cell cytoskeleton?

The cell cytoskeleton is a network of protein filaments that provides shape, support, movement, and internal organization to the cell.

What are the three main components of the cell cytoskeleton?

The three major components are microfilaments, intermediate filaments, and microtubules.

What is the main function of the cell cytoskeleton?

The cell cytoskeleton maintains cell shape, enables cell movement, transports organelles, and plays an important role during cell division.

Is the cell cytoskeleton present in plant and animal cells?

Yes. The cell cytoskeleton is present in both plant and animal cells, where it provides structural support and helps coordinate cellular activities.

Why is the cell cytoskeleton important?

The cell cytoskeleton is essential for maintaining cell integrity, intracellular transport, chromosome separation during cell division, and cell signaling.

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