Light Dependent Stage

• In thylakoids, involves three processes: water splitting by light (photolysis), NADP reduced to NADPH, and ATP (photophosphorylation)

  A) Stroma

  B) Thylakoid Membrane

  C) light harvesting system

  D) energy transfer

  E) pigment

  F) Accessory pigments

  G) reaction centre

  H) primary pigment reaction centre

  I) Thylakoid Space

  
• Light is absorbed by individual chlorophylls in light-harvesting complexes, transferring energy to chlorophyll a at reaction centre as resonance energy, releasing two electrons
• Two paths, depending where electrons end up: Cyclic photophosphorylation uses only PSI, produce ATP if electrons pass back to the same reaction centre PSI and non-cyclic photophosphorylation uses PSI and PSII, produce ATP and NADPH