Question

Describe the structures that make up the cytoskeleton.

Answer 1

The cytoskeleton is made up of:

1. Microtubules:

1. It is a cylindrical tube measuring 20-25 nm in diameter.
2. It is composed of sub-units of protein tubulin (α and β sub-units)

Functions:

• It determines the cell shape.
• Formation of spindle fibres during mitosis.
• Conduction of nerve impulses.
• Cilia and flagella movement..

2. Microfilaments:

1. These are fine thread-like protein fibres, made up of contractile protein – actin.
2. They measure about 50A^o in diameter.

Functions:

• Mechanical support.
• In the muscle cells, they help in movement and locomotion.
• In microvilli, they help in absorption.

3. Intermediate filaments:

1. They are ultramicroscopic structures present in the cytoplasm or in between the cells.
2. Tough unbranched protein fibres measuring about 10 nm in diameter.

Functions:

• Impart structural stability to the cell.
• Mechanical (tensile) strength to the cell.
• Example: Keratin.