Photosynthesis Light + 6CO2 + 6H2O  C6H12O6 + 6O2 -------------------------------------------------------------------------- Sunlight + Carbon + Water = Glucose + Oxygen dioxide

Photosynthesis Photo = Light Synthesis = to make or build Photosynthesis reactions are broken down into 2 main sections Light Reactions Photolysis Calvin Cycle Electron Transport Chain Dark Reactions

Chloroplast Link

Converting Light Energy To Chemical Energy Chapter 6 Converting Light Energy To Chemical Energy The pigments are grouped in clusters of a few hundred molecules in the thylakoid membrane. Each cluster and the proteins that the pigment molecules are embedded in are referred to collectively as a photosystem. By absorbing light, pigment molecules in photosystem I and photosystem II acquire some of the energy carried by the light.

Photolysis The splitting of water into 2H+ and O- The 2H+ is then absorbed by NADP+ Nicotinamide Dinucleotide Phosphate The NADP acts as a carrier for the 2 Hydrogens (2H+)

Light Reactions Steps # 1-6 Light Strikes the Chlorophyll molecule The electrons inside the Chlorophyll absorbs the suns energy The electrons leave the Chlorophyll and are passed along a series of other reactions called the Electrons Transport Chain (ETC) The chlorophyll also absorbs the lost e- from splitting the water molecule from photolysis

Light Reactions During the Electron Transport Chain the electrons gain more energy The energy is stored as ATP 6. The ATP is then sent to the Calvin Cycle

Light Reactions

Calvin Cycle

The Calvin Cycle CO2 from the environment is bonded to a 5 carbon molecule This forms a 6 carbon molecule This is called carbon fixation The carbon from the CO2 is fixed (attached) into a usable form

Calvin Cycle Water is added to a 6 carbon molecule which splits into 2 equal pieces Some of the 3 carbon molecules are combined to form sugars using: Hydrogens from the NADPH from photolysis Energy from ATP

Calvin Cycle Continued The other 3 carbon molecules may form a 5 carbon molecule to be reused in the cycle again The energy used to bond the 3 carbon molecules together comes from ATP

Calvin Cycle

Electron transport chain

Dark Reactions (Chemosynthesis) Chemo = Chemicals Autotrophic organisms that create energy from organic molecules This requires no Oxygen Produces methane gas Involves most bacteria

Assignment Text 118 & 124