What are the two stages in …

The process of photosynthesis occurs in two stages:

Light-dependent reaction or light reaction:

• Photosynthesis begins with the light reaction which is carried out only during the day in the presence of sunlight. In plants, the light-dependent reaction takes place in the thylakoid membranes of chloroplasts.
• The Grana, membrane-bound sacs like structures present inside the thylakoid functions by gathering light and is called photosystems.
• These photosystems have large complexes of pigment and proteins molecules present within the plant cells, which play the primary role during the process of light reactions of photosynthesis.

The chemical equation in the light reaction of photosynthesis can be reduced to:

2H₂O + 2NADP+ + 3ADP + 3Pi → O₂ + 2NADPH + 3ATP

Light independent reaction or dark reaction

• Dark reaction is also called carbon-fixing reaction.
• It is a light-independent process in which sugar molecules are formed from the water and carbon dioxide molecules.
• The dark reaction occurs in the stroma of the chloroplast where they utilize the NADPH and ATP products of the light reaction.
• 3CO₂ + 6 NADPH + 5H₂O + 9ATP → G3P + 2H+ + 6 NADP+ + 9 ADP + 8 Pi