What is the role of water in photosynthesis?

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy. In photosynthesis, light energy is captured and used to convert water and carbon dioxide into oxygen and sugar. This occurs in two steps:
STEP 1. LIGHT REACTIONS
In this step, solar energy (light) is converted into chemical energy (ATP). The cell absorbs the light and uses the light energy to split a water molecule and transfer the electron, producing NADPH and ATP.
STEP 2. THE CALVIN CYCLE
The Calvin cycle uses the NADH and ATP created by the light reactions to produce sugar.
The sugar created by photosynthesis is polymerized (combined into long chains) and stored as polymers of glucose. This glucose is consumed by other organisms or used by the plant itself to produce energy by cellular respiration. The role of water in photosynthesis is to be split by light energy and supply the electrons used to produce ATP.