During the light dependent reaction, chlorophyll in the chloroplasts within a plant cell will absorb light energy, this will then excite electrons and an electron will be removed from the chlorophyll, once this electron has been excited, it will enter the electron transport chain, during this process they will release energy. This energy is used to combine ADP (Adenosine Diphosphate) and Pi (inorganic phosphate) to form ATP (Adenosine Triphosphate), this process is called photo-phosphorylation. Water is split up in the process of photolysis to form electrons, as well as hydrogen ions and oxygen, these electrons released are used to reduce NADH (an electron carrier). These products then move onto the light independent reaction.