The fate of solar energy

1. 0 • A new flower species has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment? • red and yellow • blue and violet • green and yellow • blue, green, and red • green, blue, and violet

2. The fate of solar energy

3. BIG PICTURE THEMES! • Compare with mitochondria - both involved with cellular energetics • Overall - how do the various parts of photosynthesis fit together? • Science as process - how do we know?

4. Science as Process: How do we know….. • where evolved oxygen comes from? • what wavelengths of light are used and what pigments absorb them? • chlorophyll molecules work together in photosystems? • photosystems II and I work together? • evidence for chemiosmosis? • the pathway for carbon fixation?

5. Figure 8.1 Focusing in on the location of photosynthesis Cuticle Epidermis Vascular bundle Mesophyll Stoma Vacuole Inner membrane Cell wall Outer membrane Chloroplast Thylakoid Stroma Granum Thylakoid Membrane

8. Part of a single chloroplast Thylakoids Grana Stroma

9. Photosynthesis Respiration

10. Can you draw these?

11. ~1.5 BYA ~2.5 BYA

12. Oxygenic photosynthesis Anoxygenic photosynthesis

13. CO2 + H2O  CH2O + O2 • Where does oxygen come from? CO2 or H2O? • Two lines of evidence: • Van Neil’s experiments - LOGIC. • Experiments with radioisotopes

14. Van Neil’s logic: Analogy Oxygenic photosynthesis Anoxygenic photosynthesis CO2 + 2 H2S → CH2O + 2 S + H2O CO2 + 2 H2O → CH2O + O2+ H2O

15. Van Neil’s experiments suggested water on both sides: CO2 + 2 H2O → CH2O + O2+ H2O 6 CO2 + 12 H2O  C6H12O6 + 6 H2O + 6 O2 Simplified: 6 CO2 + 6 H2O  C6H12O6 + 6 O2

16. Using 18O 6CO2 + 12H2O C6H12O6 + 6O2+ 6H2O 6CO2 + 12H2O C6H12O6 + 6O2+ 6H2O 6CO2 + 12H2O  C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O  C6H12O6 + 6O2 + 6H2O

17. Figure 8.1 Focusing in on the location of photosynthesis Cuticle Epidermis Vascular bundle Mesophyll Stoma Vacuole Inner membrane Cell wall Outer membrane Chloroplast Thylakoid Stroma Granum Thylakoid Membrane

18. An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle

19. An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle

20. An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle

21. Sunlight Photosystem H2O O2 Thylakoid Light-Dependent Reactions NADPH NADP+ ADP+Pi ATP Calvin Cycle CO2 Organic molecules Stroma Fig. 8.2. Light-dependent and Light-independent (Calvin cycle) reactions

23. Fig. 8.4. The electromagnetic spectrum Increasing energy Increasing wavelength 0.001 nm 1 nm 10 nm 1000 nm 0.01 cm 1 cm 1 m 100 m UV light Gamma rays X-rays Infrared Radio waves Visible light 400 nm 430 nm 500 nm 560 nm 600 nm 650 nm 740 nm

24. http://www.phschool.com/science/biology_place/biocoach/photosynth/electro.htmlhttp://www.phschool.com/science/biology_place/biocoach/photosynth/electro.html

26. Why leaves are green: interaction of light with chloroplasts