Splitting of Water

A natural question arises: how does PS II supply electrons continuously, when its own electrons keep leaving for the electron transport chain? The electrons that were moved out of photosystem II must be replaced. This is achieved by electrons made available due to the splitting of water.

The splitting of water is associated with PS II. Water is split into 2H+, [O] and electrons:

2H₂O → 4H⁺ + O₂ + 4e⁻

• This reaction creates oxygen, which is one of the net products of photosynthesis.
• The electrons released by splitting water replace those removed from PS II, and ultimately the electrons needed to replace those removed from PS I are provided by PS II. …