Note on light dependent reactions: 

1. Light dependent reactions are also called as photochemical phase. 

2. The light dependent reaction takes place in chlorophyll containing thylakoids called grana of chloroplasts. 

3. Several steps occur in the light dependent reaction. 

4. Step – 1: The chlorophyll on exposure to light energy becomes activated by absorbing photons.

5. Step – II: The energy is used in splitting the water molecule into two component ions named hydrogen (H⁺), hydroxyl ion (OH^-). This reaction is known as photolysis. 

6. Step – III: OH^- ions through a series of steps produce water (H₂O) and O₂. 

7. The end products of light reaction are ATP, NADPH and O₂. 

Note on dark reaction or light independent reaction: 

1. In light independent phase the hydrogen of the NADPH is used to combine it with CO₂, by utilizing ATP energy and to produce glucose. 

2. This synthesis occurs in a number of steps using certain special intermediate compounds (mainly RUBP – Ribulose hi phosphate) and enzymes. Finally glucose is converted to starch. 

3. All these reactions occur in the stroma region of the chloroplast.