Biology / Unit 3 Bio 0593 short lesson, about 20 seconds
Photosystem II and the Splitting of Water
Captions available
The idea
Photosystem II's reaction center loses a high-energy electron to the electron transport chain and replaces it by splitting water, releasing oxygen as a byproduct.
In practice
Splitting two water molecules at photosystem II releases one molecule of oxygen gas, the oxygen every aerobic organism breathes.
Where people slip
Water splitting exists to replace the lost electron — oxygen release is a byproduct, not the reaction's purpose.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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