During the light dependent reaction of photosynthesis, light energy is converted to the energy currency of ALL cells. This energy-carrying molecule is needed to produce glucose. This molecule is

ATP stands for Adenosine Triphosphate which is known as the energy currency of the cell. It is produced during the light-dependent reactions of photosynthesis and gets used up during the light-independent reaction or the Calvin cycle in order to produce food for the plants which is glucose( gets stored as starch).