Overview of Photosynthesis

Autotrophs vs. Heterotroph Autotrophs produce their own food Plants are autotrophs Heterotrophs obtain energy from food that they eat Animals are heterotrophs

Equation for Photosynthesis: 6CO2 + 6H2O C6H12O6 + 6O2 sunlight Carbon Dioxide Water Glucose Oxygen

The Reactions Photosynthesis occurs in the chloroplast and consists of two parts: Light dependent Light independent (dark) (Page 209)

The Light Reaction The light reaction occurs in the thylakoid (disks in the chloroplast)

The Light Reaction Light energy is absorbed by the chlorophyll in the chloroplast “Excited” electrons are passed along a series of carrier molecules called the electron transport chain (ETC) to form NADPH

The Light Reaction Water is split and oxygen gas is released into the air A phosphate is added to ADP to make ATP

These are high energy compounds The Light Reaction This process uses: water, ADP, and NADP+ This process produces: oxygen, NADPH, and ATP These are high energy compounds

The Dark Reaction The dark reaction occurs in the stroma (liquid in the chloroplast) Also known as the Calvin Cycle

The Dark Reaction ATP & NADPH from the light rxns contain chemical E- but not stable for long term E use Only a few minutes Dark rxn creates E sugars that can be used for longer amounts of time (GLUCOSE)

The Dark Reaction CO2 from air is “fixed”, which means it is made into usable form ATP, NADPH, and CO2 go through a series of reactions to produce glucose (sugar)

Equation for Photosynthesis: 6CO2 + 6H2O C6H12O6 + 6O2 sunlight Carbon Dioxide Water Glucose Oxygen