1. End Show Slide 1 of 28 8-2 Photosynthesis: An Overview The key cellular process identified with energy production is photosynthesis. The Photosynthesis Process: green plants use sunlight energy and convert water and carbon dioxide into high- energy carbohydrates and oxygen. Copyright Pearson Prentice Hall

2. End Show Slide 2 of 28 8-2 Photosynthesis: An Overview Copyright Pearson Prentice Hall Investigating Photosynthesis What did the experiments of van Helmont, Priestley, and Ingenhousz reveal about how plants grow?

3. End Show Slide 3 of 28 8-2 Photosynthesis: An OverviewInvestigating Photosynthesis Van Helmont concluded that the gain in mass came from water because water was the only thing he had added. Priestley then placed a live sprig of mint under the jar and allowed a few days to pass. His conclusion, the plant releases O2. Ingenhousz’s experiments showed that light is necessary for plants to produce oxygen. Copyright Pearson Prentice Hall

4. End Show Slide 4 of 28 8-2 Photosynthesis: An OverviewThe Photosynthesis Equation The key cellular process identified with energy production is photosynthesis. Photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Copyright Pearson Prentice Hall

5. End Show Slide 5 of 28 8-2 Photosynthesis: An Overview Copyright Pearson Prentice Hall The Photosynthesis Equation The key cellular process identified with energy production is photosynthesis. 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Light (reactants)(products)

6. End Show Slide 6 of 28 8-2 Photosynthesis: An Overview Copyright Pearson Prentice Hall The Photosynthesis Equation O2O2 CO 2 + H 2 0 Sugar ADP NADP + Light-Dependent Reactions (thylakoids) H2OH2O ATP NADPH Calvin Cycle (stroma) Light energy

7. End Show Slide 7 of 28 8-2 Photosynthesis: An OverviewLight and Pigments How do plants capture the energy of sunlight? In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll. Copyright Pearson Prentice Hall

8. End Show Slide 8 of 28 8-2 Photosynthesis: An OverviewLight and Pigments Plants gather the sun's energy with light- absorbing molecules called pigments. The main pigment in plants is chlorophyll. There are two main types of chlorophyll: –chlorophyll a –chlorophyll b Copyright Pearson Prentice Hall

9. End Show Slide 9 of 28 8-2 Photosynthesis: An OverviewLight and Pigments –Plants gather the sun's energy with light-absorbing molecules called pigments. Chlorophyll absorbs light in the blue-violet and red regions of the visible spectrum. Chlorophyll reflects green light, which is why plants look green Copyright Pearson Prentice Hall Estimated Absorption (%) 400 450 500 550 600 650 700 750 Wavelength (nm)

10. End Show Slide 10 of 28 8-2 Photosynthesis: An OverviewLight and Pigments –Photosynthesis Steps: 1. Chlorophyll absorbs light energy 2. Chlorophyll transfers energy to electrons 3. Electrons are, “excited” 4. Excited electrons make photosynthesis work. Copyright Pearson Prentice Hall

11. End Show Slide 11 of 28 Copyright Pearson Prentice Hall 8-2 In van Helmont's experiment, most of the added mass of the tree came from a.soil and carbon dioxide. b.water and carbon dioxide. c.oxygen and carbon dioxide. d.soil and oxygen.

12. End Show Slide 12 of 28 Copyright Pearson Prentice Hall 8-2 Plants use the sugars produced in photosynthesis to make a.oxygen. b.starches. c.carbon dioxide. d.protein.

13. End Show Slide 13 of 28 Copyright Pearson Prentice Hall 8-2 The raw materials required for plants to carry out photosynthesis are a.carbon dioxide and oxygen. b.oxygen and sugars. c.carbon dioxide and water. d.oxygen and water.

14. End Show Slide 14 of 28 Copyright Pearson Prentice Hall 8-2 The principal pigment in plants is a.chloroplast. b.chlorophyll. c.carotene. d.carbohydrate.

15. End Show Slide 15 of 28 Copyright Pearson Prentice Hall 8-2 The colors of light that are absorbed by chlorophylls are a.green and yellow. b.green, blue, and violet. c.blue, violet, and red. d.red and yellow.