1. © 2010 Pearson Education, Inc. Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint ® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Chapter 7 Photosynthesis: Using Light to Make Food

2. © 2010 Pearson Education, Inc. THE BASICS OF PHOTOSYNTHESIS Photosynthesis: –Is used by plants, some protists, and some bacteria –Transforms light energy into chemical energy –Uses carbon dioxide and water as starting materials The chemical energy produced via photosynthesis is stored in the bonds of sugar molecules.

3. © 2010 Pearson Education, Inc. Organisms that use photosynthesis are: –Photosynthetic autotrophs –The producers for most ecosystems

4. © 2010 Pearson Education, Inc. Chloroplasts: Sites of Photosynthesis Chloroplasts are: –The site of photosynthesis –Found mostly in the interior cells of leaves

5. © 2010 Pearson Education, Inc. Stomata are tiny pores in leaves where carbon dioxide enters and oxygen exits.

6. Leaf cross section Stomata Vein CO 2 O2O2 Figure 7.2-1

7. Carbon dioxide 6 O 2 6 CO 2 6 H 2 O C 6 H 12 O 6 Water Glucose Photo- synthesis Oxygen gas Light energy Figure 7.UN1 The Overall Equation for Photosynthesis In the overall equation for photosynthesis, notice that: The reactants of photosynthesis are the waste products of cellular respiration.

8. © 2010 Pearson Education, Inc. Sunlight energy enters ecosystem Photosynthesis Cellular respiration C 6 H 12 O 6 Glucose O 2 Oxygen CO 2 Carbon dioxide H 2 O Water drives cellular work Heat energy exits ecosystem ATP Figure 6.2

9. THE LIGHT REACTIONS: CONVERTING SOLAR ENERGY TO CHEMICAL ENERGY Chloroplasts: –Are chemical factories powered by the sun –Convert solar energy into chemical energy © 2010 Pearson Education, Inc.

10. Visible light Wavelength (nm) Radio waves 380 400 500 600 750 700 Wavelength = 580 nm Micro- waves Gamma rays Infrared UV X-rays 10 –5 nm 10 –3 nm10 3 nm 1 nm 10 6 nm 1 m1 m 10 3 m Increasing wavelength Figure 7.4

11. © 2010 Pearson Education, Inc. Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint ® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Fig. 7-05 Bacterium Wavelength of light (nm) 400 500 600 700 Light Number of bacteria Algal cells Prism Microscope slide

12. Figure 7.7