Photosynthesis. Name. Light reactions Calvin cycle Oxidation Reduction Electronegativity Photosystem Electron carrier NADP+ Concentration gradient

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1 Vocabulary Terms Photoautotroph Chemoautotroph Electromagnetic spectrum Wavelength Chloroplast Thylakoid Stroma Chlorophyll Absorption spectrum Photosynthesis Light reactions Calvin cycle Oxidation Reduction Electronegativity Photosystem Electron carrier NADP+ Concentration gradient Potential energy ATP synthetase (synthase) Chemiosmosis Electron transport chain Photosystem I Photosystem II Rubisco (RuBP carboxylase) Photorespiration Pigments 4.1 Autotrophs 1. All organisms need a source of and. 2. Define and give an example of each: Photoautotroph Chemoautotroph Heterotroph 4.2 Overview of Photosynthesis 3. Define wavelength. 4. What two properties does the wavelength of light determine? 5. What is the lowest energy light of the EMS? The highest? 6. Does visible light have much energy? 7. What color of visible light has the most energy? The least?

2 8. What kinds of molecules absorb light (photons)? 9. Where are the pigments located in a plant cell? (Be specific!!) 10. What is the photosynthetic organelle of a plant? 11. Label the diagram of a chloroplast below. Include the stroma, thylakoids, grana, and indicated where the pigments are located. Summarize the functions of the thylakoid and stroma!! Granum Thylakoids Stroma Outer membrane Inner membrane Intermembrane space Location of photosystems Site of Calvin Cycle 12. The major pigment of plants is. 13. What colors of light does chlorophyll absorb? 14. What color of light does chlorophyll not absorb? (Why are plants green) 15. What is the role of accessory pigments? 16. Summarize Figure 4.5. What wavelength of light would be most effective for photosynthesis? 17. Which wavelength is least effective?

3 18. Write the overall equation for photosynthesis. Indicate which substance is oxidized and which is reduced. 19. What are the two stages of photosynthesis, briefly describe what happens during each stage then complete the diagram below: Stage Events

4 4.3 - The Light Reactions Before starting this section, you may wish to review oxidation and reduction. 24. Summarize the light reactions below: Reactants Products 20. Which contains more potential energy, an oxidized or reduced molecule? Indicate which reactant is reduced and what is oxidized during the light reactions. 21. What is a photosystem? Where are photosystems found? 22. Describe what happens at: a. Photosystem (PSII) when light hits b. PSI when light hits 23. How is the electron that is lost from PSI replaced? 24. How is the electron that is lost from PSII replaced?

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6 25. NADP+ is an electron shuttle that accepts and carries electrons around in a cell. Where does NADP+ accept an electron from and what does it become upon doing this? 26. What does the movement of electrons power? 27. Is the movement of H+ into the thylakoid space an example of passive for active transport? 28. What type of energy is created as a H+ gradient is formed? 29. If ph = -log [H+], which side of the thylakoid should become acidic? 30. Why is it possible to build up a proton (H+) gradient in the thylakoid? (Why don t the protons diffuse out?) 31. What is the potential energy of the H+ gradient used to produce? 32. What was the name of this process? (See Appendix 4A in your text book.) 33. What are the products of the light reactions and where does each go?

7 4.4 The Calvin Cycle 34. Summarize the Calvin cycle below: Reactants Products 35. Why does a plant bother with the Calvin cycle is ATP is produced in the light reactions? 36. Where does the Calvin cycle occur? 37. What does CO 2 fixation mean? 38. What is the role of Rubisco in the Calvin cycle? (What is its more formal name?) 39. What is the acceptor of CO 2? How many carbons does it have? 40. A six carbon intermediate is formed after CO 2 fixation. What happens to this intermediate? 41. One PGAL can be removed from the cycle after three turns to form what? 42. What are the rest of the PGAL molecules used for? 26. For each PGAL molecule that exits the Calvin cycle: molecules of CO 2 enter the cycle molecules of ATP are used molecules of NADPH are used turns of the Calvin cycle are required

8 27. What are the possible fates of PGAL (see Figure 4.14)? 28. For each glucose molecule produced by photosynthesis: molecules of CO 2 are used molecules of ATP are used molecules of NADPH are used turns of the Calvin cycle are required 43. Will the Calvin cycle proceed if the light reactions stop? Why or why not? 44. If you gave plant #1 radioactive CO 2 and plant #2 radioactive H 2 O, which plant will release radioactive O 2? Why? 45. Active transport and diffusion both occur during photosynthesis. Describe when and where each process occurs. 46. Define oxidation and reduction. Summarize the various points during photosynthesis that these processes occur.

9 Photosynthesis and The Environment; Chemoautrophy 4.5 and Rate of Photosynthesis and Photorespiration (In the interest of time, we will not discuss C4 and CAM plants.) 1. What are the units of rate? 2. How could the rate of photosynthesis be measured? 3. Describe how each of the following three factors affects the rate of photosynthesis. And WHY!! Try to summarize in both words and a graph. a. Light intensity b. Temperature c. Concentration of CO 2 d. Concentration of O 2 4. What is a limiting factor?

10 5. Define photoinhibition and photorespiration. Why does photorespiration occur? 4.7 Photosynthesis and the Atmosphere 6. Photosynthesis and respiration form a cycle. Describe two things that cycle between the two processes and indicate HOW they cycle. 7. How are the organic molecules produced as a result of photosynthesis important to you and other heterotrophs? 8. What affect impact does the increase in fossil fuels by humans have on this cycle? What might be the net result of this activity?