3. Introduction to Photosynthesis

4. Objectives Discuss energy flow through living systems Identify the parts of a leaf Outline the process of photosynthesis

5. Overview Plants convert the energy of sunlight into the energy of chemical bonds of carbohydrates

6. Importance of Photosynthesis Provides energy for plants Provides energy for animals that eat plants Provides energy for animals that eat animals that ate plants Provides energy for organisms that break down all of the above Provides the energy for most ecosystems on earth

7. But that’s not all.. Gives us food Provides wood, paper, other wood based products Provides cotton, hemp, other fibers Is the original source of energy in coal and oil Plants are pretty

8. But wait, there’s more.. Photosynthesis consumes Carbon Dioxide And Produces Oxygen

9. History Jan Van Helmont Found the mass of a pot of soil and a seedling. Watered the seedling for five years. Found the mass again Concluded that the increase in mass came from water

10. History Joseph Priestly Found that a candle goes out when placed in a jar. However, the candle keeps burning if a sprig of mint is also placed in the jar. Concluded that plants produce [Oxygen]

11. History Jan Ingenhousz Showed that Priestley’s experiment only works in the light. Concludes that light is necessary for plants to produce oxygen

12. History Magic School Bus class

13. CO 2 +H 2 0 C(H 2 O)+O 2 Chemical basis of photosynthesis Light

14. 6CO 2 +6H 2 0 C 6 H 12 O 6 +6O 2 Balanced Equation Light

15. CO 2 +H 2 0C(H 2 O)+ O 2 Photosynthesis Respiration Sun Entropy The BIG Picture

16. Leaf Structure – p.655

17. Leaf structure

18. Requirements for Photosynthesis

19. Light Mostly violet, blue and red wavelengths from the visible spectrum

20. Pigments Substances that absorb certain wavelengths of light and reflect other wavelengths Thus they are coloredExamples:Chlorophyll (a and b) – greenCarotene – red/orangeXanthophylls - yellow

21. Energy Storing Compounds Energy trapped by molecules can be used to lift electrons to a higher energy level. From that higher energy level the electrons can fall down to their original energy level and do work along the way. Example – a solar cell that powers a calculator

22. Or… The high-energy electrons can be bound to an electron carrier. Nicotinamide Adenine Dinucleotide Phosphate NADP+ accepts a pair of high energy electrons and a Hydrogen ion to become NADPH

23. And of Course ATP – Adenosine Triphosphate Energy storing compound used by every living cell Provides the energy for almost all cellular functions

24. Function of ATP ATP If the cell need energy it breaks ATP into ADP+P ADP+P If the cell has energy to store it makes ATP

25. Overview of Photosynthesis Light reactions Dark reactions – Calvin Cycle

26. Light Reactions Energy from sunlight is trapped, water molecules are split, NADPH and ATP are formed, O2 is given off as a waste gas

27. Calvin Cycle Products from the light reactions and CO 2 from the atmosphere are used to produce carbohydrates

28. Objectives 1.Discuss energy flow through living systems 2.Identify the parts of a leaf 3.Outline the process of photosynthesis

29. Homework See planner.

30. Have a nice day