Question

How does the light-dependent reaction differ from the light-independent reaction? What are the end product and reactants in each? Where does each reaction occur within the chloroplast?

Answer 1

Light-dependent photosynthesis is called Hill reaction or Light reaction. The Light independent reactions are called the Biosynthetic phase.

Light-dependent reaction	Light independent reaction
1. It is called Hill reaction or Light reaction.	1. It is called the Dark reaction or Biosynthetic pathway or the Calvin cycle.
2. The reaction is carried out in Thylakoid membranes (Grana) of the chloroplast.	2. This reaction is carried out in the stroma of the chloroplast.
3. Photosynthetic pigments absorb the light energy and convert it into chemical energy ATP and NADPH2.	3. CO2 is reduced into carbohydrates with the help of light-generated ATP and NADPH2.
4. It is carried out in the presence of light.	4. It is carried out in the absence of light.

In the light-dependent reaction, the chlorophyll absorbs the light energy and converts it into chemical energy ATP and NADPH₂. In the light-independent reaction, CO₂ is reduced into carbohydrates with the help of light-generated ATP and NADPH₂. The light-dependent reaction is carried out in the Grana of the chloroplast. The Light independent reaction is carried out in the stroma of the chloroplast.