Cell Organelles: Microtubules, Microfilament, Vacuoles, Cilia and Flagella | Biology Grade XI

Science Notes

Cell Organelles: Microtubules, Microfilament, Vacuoles, Cilia and Flagella

a) Microtubules

Microtubules are long cylindrical hollow tube found in cytoplasm. They are made up of tubulin protein. Each triplet fibrils of centriole is made up of one microtubules. It provides mechanical support to cell and helps in cell division.

b) Microfilament

They are long cylindrical solid tubes found in cytoplasm. The function is helps in cyclosis, locomotion, and cell division

c)  Vacuoles

They are single membraed sac like structures, which is filled with liquid mass called vacuolar sap (cell sap). Its membrane is called tonoplast.

Function of the vacuole

It stores various organic and inorganic molecules, it balances the water in cell, it also helps in growth and elongation of cells, cell sap exerts turgor pressure, which keeps the plant cell turgid.

d) Cilia and Flagella

They are hair like structures. They rise from basal bodies; they are made up of 11 filaments and fibrils. In 11 fibrils, nine fibrils are arranged in outer ring and two fibrils remains at centre. Outer filament consists of two microtubules a and b. Microtubules are connected by radial spoke with central fibrils.

Difference between Cilia and Flagella:



  1. It is shorter and smaller in size Covers entire cell surface
  2. Cilia shows sweeping movement
  3. Helps in locomotion and to capture food


  1. It is longer and larger in size.
  2. Usually one or two flagella are found at one end of cell.
  3. Flagella show undulating movement. Flagella helps in locomotion


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