Light Dependent Reactions

• Plants use PS 1 and PS 2 to produce ATP and NADH

• This is a 2-part process called non-cyclic phosphorylation

Non-Cyclic Phosphorylation

Photo-system II

• light energy hits P680 and excites an electron of reaction center chlorophyll a

• the e- is captured by primary electron accept-or which initiates ETC

• the e- lost by the chlorophyll a molecule in P680 are replenished by coupling the photooxidation of chlorophyll a to the photolysis of water

• a water-splitting complex in the thylakoid lumen splits water into oxygen, hydrogen ions (protons, H+), and electrons

• the oxygen is released into the atmosphere as a waste product. The electrons are used to replace the es lost by the P680 chlorophyll a

Photo-system I