Exciting electrons
Photoionisation: the loss of an electron from chlorophyll after the pigment absorbs light.
At photosystem II (PSII), light absorbed by chlorophyll raises electrons to a higher energy level.
These excited electrons leave the chlorophyll and are taken up by carrier proteins within the thylakoid membrane.
- Photoionisation leaves the chlorophyll short of electrons.
- The released electrons have gained energy from light.
- They enter the electron transfer chain.
Electrons released when water is split later replace those lost from PSII.