Question

why should the light dependent reaction occur before the light independent reaction ​

Answer 1

In the light-independent reactions or Calvin cycle, the energized electrons from the light-dependent reactions provide the energy to form carbohydrates from carbon dioxide molecules. ... After the energy is transferred, the energy carrier molecules return to the light-dependent reactions to obtain more energized electrons.

Answer 2

Answer:

In light – dependent photosynthesis, the photosynthetic pigment absorbs the light energy and convert it into chemical energy, ATP and NADPH2 . These products move out from grana to the stroma of the chloroplast for the light-independent reactions (Dark reaction or Biosynthetic pathway). During this reaction, CO2 is reduced in the carbohydrates with the help of light generated ATP and NADPH2 . So the light-dependent reaction should occur before the light-independent reaction.