Phases of Photosynthesis


 
 
Concept Explanation
 

Phases of Photosynthesis

Photosynthesis is the process used by plants, algae and certain bacteria to harness energy from sunlight and turn it into chemical energy. The process basically involves formation of organic food from inorganic substances in the presence of sunlight.

The process of photosynthesis takes place in the mesophyll cells in a leaf are the principal centres of this activity. During daytime, when sunlight falls on the leaf, the light energy is trapped by the chlorophyll of the upper layer of mesophyll, especially the palisade cells. This energy is utilized in chemical processes involved in the manufacture of food, where the raw materials used are carbon dioxide and water.

There are basically two phases of photosynthesis :-

  • Light dependent phase( Photo chemical phase) 
  • Light independent (Dark) Phase(Biosynthetic phase) 
  • Light dependent phase( Photo chemical phase) :-

    In this phase, light plays the key role. A series of chemical reactions occur in very quick succession, initiated by light and therefore, the phase is called the photochemical phase. The light reaction takes place in thylakoids  of the chloroplast.

    Light independent phase(Dark phase) or Biosynthetic phase:-

    The light independent reactions of photosynthesis take place with in the stroma. It contains enzymes that work with ATP and NADPH to 'fix' carbon from carbon dioxide into molecules that can be used to build glucose.       

     
     
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