1. Converting Light Energy into Chemical Energy
Photosynthesis
Converting Light Energy into Chemical Energy

2. I. Photosynthesis Background
Photosynthesis drives and supports all life on earth (except at hydrothermal vents). Understanding this important reaction will help us better understand the limits and effects of human and other populations on our planet.
Sun provides energy->
Plants make food->
Consumers eat plants->
Consumers thank plants!

3. I. Photosynthesis B. Location Plant Cell
The reactions of photosynthesis occur within plant cells in the chloroplast. Chloroplasts contain pigments called chlorophyll, which capture light.
C. Products & Reactants of Photosynthesis
Light Energy
Sugar + O2
CO2 + H2O

4. D. Overview of Photosynthesis -
In the chloroplasts of photosynthetic organisms, the energy of sunlight is transformed into the energy stored in the chemical bonds of carbohydrates (glucose)
CO2
H2O
Light
Chloroplast
Captured by rubisco enzyme O2
Other materials
Calvin
Cycle:
Chlorophyll absorbs light for light reactions
Dark (Light-
Independent)
Reactions
Energy:
Light- Dependent Reactions
H+ ions
Dark Reactions
ATP
NADPH
Sugar (Glucose)
C6H12O6
Q: What happens to the glucose after it is made by the plant cell?

5. E. A Closer Look at Photosynthesis
1. Light Reactions (Light Dependent)
Light energy, absorbed by chlorophyll, splits water to store chemical energy (ATP), releasing hydrogen and oxygen
H2O + light  ATP (energy) + H+ + O2
2. Dark Reactions (Light Independent)
The energy generated in the light reaction converts carbon dioxide and hydrogen ions into sugar (glucose)
ATP(energy) + H+ + CO2  C6H12O6 (+ ADP +P)
Q: What is ATP?

6. ATP: adenosine triphosphate
the form of stored energy that is useable by cells
Energy is stored and/or released when bonds between the phosphates are formed or broken