1. Photosynthesis

2. Journey Into a Leaf

3. Plant Stomata

4. Water and Oxygen

5. Overall Equation
Is this a Redox Reaction?

6. Overall Equation Is this a Redox Reaction?
Yes: electrons are still transferred from one molecule to another

7. Questions About Plants
Why do plants need water?
Why do they release oxygen?

8. Photosynthesis
To answer these questions we must first ask, how can solar light provide energy for plants?

9. Photosynthesis How can solar light provide energy for plants?
Shorter the wavelength the greater the energy

10. Solar Radiation
Solar radiation is absorbed by chlorophyll (pigments in the thylakoids)
Why are plant leaves green?
All other colors (wavelengths) are absorbed

11. Chloroplast Pigments Chlorophyll a Chlorophyll b Carotenoids
Many others…why?
Why reflect green?

12. Photosynthesis Two Stages You need to know Light Reactions
Calvin Cycle
You need to know
The main purpose of each stage
Where they take place

13. Photon Absorption
What happens when a photon is absorbed by a pigment?

14. The Photosystem
Energy (not electrons) is passed from one pigment to the next until it reaches the reaction center

15. Making ATP & NADPH
The pigment in the reaction center will give up its excited electron to an electron acceptor
Conversion of light energy to chemical energy
What can cells do with captured electrons?

16. Electron Flow & Potential Energy

17. A Familiar Processes

18. The Calvin Cycle

19. Summary

20. Problem with Photosynthesis
Photorespiration
When its hot out, stomata close up…why is this a problem? CO2 can’t get into cell and O2 can’t leave
O2 then enters Calvin Cycle
Sugar production stops because there’s no carbon source

21. Photorespiration

22. The Oxygen Revolution Was O2 always part of our atmosphere?
How do we know?
How and when did it happen?
What was the impact?