Quantasome Diagram, Structure and Function

In this article we will discuss about quantasome diagram, discovery, structure and function

What is Quantasome?

  • Inner surface of thylakoid membrane consists of small spherical structure is known as Quantasomes.
  • Quantasomes are also known as photosynthetic units.
  • Each quantasomes approximately contain 200 to 300 chlorophyll molecules.

Quantasome Diagram

Quantasome Diagram

Discovery of Quantasomes

  • In 1952, Steinman observed granular structures in chloroplast lamellae using an electron microscope.
  • These structures were later confirmed by Park and Biggins (1964) as the physiological units of photosynthesis. They named these units quantasomes.
  • According to them one quantasome contains about 230 chlorophyll molecules.
  • Emerson & Arnold discovered fixing one molecule of CO2 required 2500 chlorophyll molecules.
  • Therefore, approximately 10 quantasomes are required to fix one CO2 molecule.
  • However, the reduction or fixation of one CO2 requires 10 quanta of light and so each unit would contain 1/10 of 2500 i.e. 250 molecules.
  • According to Emerson 8 quanta of light are required for the release of one oxygen molecule or reduction of one Carbon dioxide molecule.
  • The quantum yield is 1/8 or 12 %.
  • No of quantum energy are utilizing to produce one molecule of oxygen is called quantum yield.

Quantasome Structure

The structure of a quantasome within thylakoid membrane consists of following parts:

  • Photosynthetic Pigments : Photosynthetic pigment such as chlorophyll and carotenoids are embedded in quantasome.
  • Light Harvesting Complex (LHC): They are made up of accessory pigments and some protein molecules.
  • Reaction Centers: Reaction centers are made up of chlorophyll a molecules.
  • Electron Transport Chain: Within the quantasome, occur the light reactions of photosynthesis.
  • Protein Matrix: Protein matrix that provides structural support and stability to the photosynthetic molecules.

Quantasome Function

  • The photosynthetic pigments are present in quantasomes are responsible for absorbing light energy from the sun light.
  • LHC in quantasome capture sun light and transfer it to the reaction centers.
  • They help in converting light energy into chemical energy.


What is quantasome in photosynthesis?

Thylakoid membrane contain small rounded units called quantasomes.

How many chlorophylls are there in one quantasome?

According Park and Biggins (1964) one quantasome contains about 230 chlorophyll molecules. Now each quantasome contain usually 200 to 300 chlorophyll molecules.

Quantasome discovered by?

Quantasome discovered by Park in the early 1960s and further confirmed by Biggins in 1964.

Difference between quantasome and photosystem?

In recent studies, the quantasomes are considered as the phtosystems. However, the existence of quantasomes now doubtful.


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