Solution :

( i ) light reaction –light plays a key role in light reaction . The phase is called as photochemical phase . The two steps in light reaction are :

Step 1 – the chlorophyll is activated when exposed to light energy .

Step 2 – the absorbed energy is utilized to split the water molecules into hydrogen and oxygen .

The hydrogen ions combine with NADP to form NADPH . The oxygen component is given out as molecular oxygen . Conversion of ADP into ATP takes place .

( ii ) dark reaction – the reaction is a phase , so it takes place along with light reaction .