1. Overview of Photosynthesis

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

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

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

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

6. 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

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

8. 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

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

10. 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)

11. 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)

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