Photosynthesis is the process by which plants and other organisms use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. Chlorophyll, located in chloroplasts, absorbs sunlight and uses the energy to convert carbon dioxide and water into oxygen and glucose through a two-step process - the light reactions and Calvin cycle. Plants appear green because chlorophyll, the main photosynthetic pigment, absorbs most wavelengths of visible light except green, which it reflects, giving leaves their green color.

1. Photosynthesis

2. THE SUN: MAIN SOURCE OF ENERGY FOR LIFE ON EARTH

4. Light Energy Harvested by Plants & Other Photosynthetic Autotrophs 6 CO 2 + 6 H 2 O + light energy -> C 6 H 12 O 6 + 6 O 2

5. Food Chain

6. THE FOOD WEB

7. WH Y AR E P LAN TS G RE EN?

8. Electromagnetic Spectrum and Visible Light Gamma rays X-rays UV Infrared & Microwaves Radio waves Visible light Wavelength (nm)

9. Different wavelengths of visible light are seen by the human eye as different colors. WHY ARE PLA NTS GRE EN? Gamma rays X-rays UV Infrared Micro- waves Radio waves Visible light Wavelength (nm)

10. Sunlight minus absorbed wavelengths or colors equals the apparent color of an object. The feathers of male cardinals are loaded with carotenoid pigments. These pigments absorb some wavelengths of light and reflect others. Reflected light

11. WHY ARE PLA NTS GRE EN? Plant Cells have Green Chloroplasts The thylakoid membrane of the chloroplast is impregnated with photosynthetic pigments (i.e., chlorophylls, carotenoids).

13. What colors are being absorbed and what colors are being reflected?

19. Different pigments absorb light differently

22. Review: Photosynthesis uses light energy to make food molecules Light Chloroplast Photosystem II Electron transport chains Photosystem I CALVIN CYCLE Stroma Electrons LIGHT REACTIONS CALVIN CYCLE Cellular respiration Cellulose Starch Other organic compounds