Capturing the Energy in Light: Photosynthesis Explained

1. Warm up In your blue books answer the following: What can make their own energy and why is that important?

2. Capturing the Energy in Light Section 6-1

3. Objectives • Describe the basic process of photosynthesis • Identify the reactants of photosynthesis • Identify the products of photosynthesis

4. Vocabulary • ADP • ATP synthase • Biochemical pathway • Calvin Cycle • Carotenoid • Chemiosmosis • Chlorophyll • Electron transport chain • Granum • Photosynthesis • Photosystem • Pigment • PGAL • Primary electron acceptor • Stoma • Stroma • Visible spectrum • Wavelength

5. Energy for Life Processes • Photosynthesis-light energy is stored • Autotrophs convert light to chemical • Stored in carbs • All life depends on autotrophs • Uses biochemical pathways (product is used in next reaction) • Uses CO2 and water

6. Light Absorption in Chloroplasts • Light reactions in chloroplasts (50+) • Thylakoids (sacs) are layered, form grana • Stroma is solution

7. Light in Pigments • Visible spectum– red to violet • Waves measured in wavelengths • Different colors, different wavelength • Pigment absorbs or reflects color

8. Chloroplast Pigments • Chlorophyll in thylakoids • Chlorophyll- “A” (light reactions), “B” (aids in absorption) • “A” absorbs less blue, more red • Both absorb little green • In leaves • Carotenoids (accessory, absorption) • Yellow, orange, and brown • In fruit

9. Summary In your blue books answer the following: Give an example of something in your everyday life that is similar to a chloroplast

10. Warm-up Answer the following in your blue books: Why do leaves change to orange, yellow, and brown in the fall? Where does the red come from?

11. Electron Transport • Each cluster of pigments is photosystem (I & II) • “B” (accessory) absorbs light, passes to “A” • For every 2 H2O • 4 H+ left in thylakoid • 1 O2 diffused out of cell

12. Chemiosmosis • ATP made from light • ATP is made from ADP and phosphate • ATP synthase makes • NADPH and ATP provide energy for Calvin Cycle

14. Summary In your blue books answer the following: What happens to the electrons in photosystem II and photosystem I?

15. Warm-up In your blue books answer the following: Summarize the electron transport chain in 10 words or less

16. The Calvin Cycle Section 6-2

17. Carbon Fixation by the Calvin Cycle • CO2 bonded into organic compounds in stroma • Calvin cycle has 3 major steps:6 turns • Made: 2 PGAL (used in macromolecules) • Used: 6 CO2, 18 ATP, 12 NADPH • Calvin Cycle

18. Alternative Pathways • CAM pathway • Plants open stomata (pores under the leaves) at night and take in CO2 • Carbon is fixed into organic compounds then sent to Calvin cycle during the day • C4pathway • stomata is partially closed during hottest part of day • Can still fix carbon when CO2 is low and O2 is high • Sent to Calvin Cycle (known as C4 plants, all others are C3 plants)

19. Chemical Equation for Photosynthesis

20. Summary In your blue books answer the following: What uses the products from photosynthesis?

21. Illuminating Photosynthesis • Photosynthesis Overview