OVERALL RX: CO₂ + 2H₂O + light--> [CH₂O] + H₂O + O₂

I.  Overview of Photosynthesis:  4 STAGES:

1. LIGHT ABSORPTION:  Electrons are pulled from water, and O₂ is evolved.  (LIGHT RX)
2. ELECTRON TRANSPORT: NADPH FORMED                                           (LIGHT RX)
3. GENERATION OF ATP                                                                                 (LIGHT RX)
4. CONVERSION OF CO₂ INTO CARBOHYDRATES                                     (Carbon RX)

II.  FORMATION and Structure OF THE CHLOROPLAST
            Outer membrane         Inner membrane
            Thylakoid                    Stroma

    Pigments are organized into light-harvesting complexes (LHC) on the thylakoid membrane.
           CHLOROPHYLL A, major photosynthetic pigment
            CHL B,  accessory pigment
            CAROTENOIDs, accessory pigment

III.  LIGHT ABSORPTION BY  PIGMENTS:
            How is light absorbed?
            What does absorbed light do?
 a.  PROPERTIES OF LIGHT

b.  CHLOROPHYLL ABSORBS A PHOTON, TRANSFERS EXCITATION ENERGY AND
Reaction Center CHL GIVES UP AN ELECTRON

A) Excitation Energy Transfer:  Light energy absorbed by pigments is transferred (funneled) to neighboring pigments and to a reaction center pigment Chl a.

b) Photochemical reaction:  The reaction center pigment chl a gives up an electron.  i.e. becomes oxidized.
[I.E. Photochemistry refers to the photo-oxidation.]

PSII:  Rx center P680 gives up an electron to acceptor pheophytin.  Water donates an electron to P680.
    2 Chl a⁺ + H₂O --> 2 Chl a + 1/2 O₂ + 2H⁺