(1) Photoionisation

• During photoionisation, chlorophyll molecules absorb light energy, causing the energy level of the electrons to be raised to a higher level (i.e. an excited state).
• The electrons become so excited that they exit the chlorophyll molecule, causing the chlorophyll to become ionised.
• The electrons that leave the chlorophyll molecule will be taken up by electron carriers. This causes the chlorophyll molecule to become oxidised, and the electron carrier to become reduced.