1. Photosynthesis Long Term Target: HS-LS1-5
Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy

2. Question:
Why are plants green?
Demo: Chromatography

3. Photosynthesis Anabolic (small molecules combined)
Endergonic (stores energy)
Carbon dioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose).
6CO H2O  C6H12O O2
glucose
SUN
photons

4. Question
With a shoulder partner…Answer: Where does photosynthesis take place? Explain the process of photosynthesis

5. Plants Autotrophs – produce their own food (glucose)
Process called photosynthesis
Mainly occurs in the leaves:
a. stoma - pores
b. mesophyll cells
Mesophyll
Cell
Chloroplast
Stoma

6. Stomata (stoma)
Pores in a plant’s cuticle through which water vapor and gases (CO2 & O2) are exchanged between the plant and the atmosphere.
Guard Cell
Oxygen
(O2)
Stoma
Carbon Dioxide
(CO2)
Found on the underside of leaves

7. Leaf Structure:

8. Chloroplast Organelle where photosynthesis takes place.
Stroma
Outer Membrane
Thylakoid
Granum
Inner Membrane
Thylakoid stacks are connected together

9. Chlorophyll Molecules
Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red- 660 nm are most important)
Plants are green because the green wavelength is reflected, not absorbed.

10. Wavelength of Light (nm)
400
500
600
700
Short wave
Long wave
(more energy)
(less energy)

11. Absorption of Light by Chlorophyll
Chlorophyll absorbs blue-violet & red light best
violet blue green yellow orange red
Absorption
wavelength

12. During the fall, what causes the leaves to change colors?
Question:
During the fall, what causes the leaves to change colors?

13. Fall Colors
In addition to the chlorophyll pigments, there are other pigments present
During the fall, the green chlorophyll pigments are greatly reduced which shows other pigments
Carotenoids are pigments that are either red, orange, or yellow

14. Two Parts of Photosynthesis

15. Two Parts of Photosynthesis
Two reactions make up photosynthesis: 1.Light-Dependent Reaction Produces energy from solar power (photons) & water (H2O) in the form of ATP and NADPH.
SUN

16. Two Parts of Photosynthesis
2.Light-Independent Reaction
(“Dark Reactions”)
Also called Carbon Fixation or Calvin Cycle
Uses energy (ATP and NADPH) from light reactions, & CO2 (from atmosphere) to make sugar (glucose).

17. Let’s take another look!

18. See any cool connections???

19. Questions?