Do Now:

1. March 14, 2011Agenda: Photosynthesis LessonPhotosynthesis WorksheetReview: Respiration ExamLab Activity 24

2. Do Now: • Pass forward light-reaction drawings 2) Describe what happens when chlorophyll absorbs light energy Electrons become excited, and are passed down the electron transport chain on the thylakoid membrane

3. Experimental set up Test tube #1: Test Tube #2: (Experimental) (Control) Light Light Chloroplasts Chloroplasts H2O H2O No CO2 CO2 If there is no CO2, very little oxygen was produced

4. AIM: Why is carbon dioxide necessary for photosynthesis?

5. Review: Photosynthesis CO2 + H2O (light energy)  C6H12O6 + O2

6. H2O  2 H2 + O2 • This reaction is very endergonic • Hydrolysis: splitting of water • Water is being OXIDIZED http://www.youtube.com/watch?v=OTEX38bQ-2w

7. If water is being oxidized, what else must happen?

8. Water is oxidized, NADP is reduced

9. On a sunny day, the light dependent reactions will occur rapidly. NADP will be reduced to NADPH. There is a limited amount of NADP in the thylakoid of the plant. …What’s the problem?

10. NADPH needs to be recycled to NADP for photosynthesis to continue to occur. • NADPH will lose its hydrogen; CO2 will act as a hydrogen acceptor

11. Dark Reactions, Light-Independent Reactions, Calvin Cycle: NADPH and CO2 will be used to make glucose.

12. Light Reactions: Summary

13. Do Now: Take out homework

14. Dark Reactions • Synthesis of glucose from NADPH2 and CO2 using ATP energy • Takes place in the stroma of the cell

15. Dark Reactions • Calvin was interested in studying the process Of the “Dark Reactions”

16. Calvin traced carbon using a radioactive isotope (C14) • Chlorella- algae

17. Do Now: Why are the following necessary for photosynthesis? • Water: donates H+’s to form a hydrogen gradient and electrons through the ETC • CO2: combines with hydrogen from NADP to produce glucose • Light- excites electrons to pass through ETC

18. Review Calvin’s Experiment • Whoops! Not THAT Calvin….

19. Calvin’s Problem: How can carbon dioxide form glucose during photosynthesis?

20. Calvin’s Experiment 1) Calvin exposes the Chlorella (algae) to radioactive C 14in C 14 O2 2) Allows photosynthesis to occur in lollipop apparatus 3) “Freezes” the reaction using ethanol alcohol a) release chlorophyll b) denature the enzymes involved in photosynthesis 4) Separates out radioactive carbon using CHROMATOGRAPHY

21. Chromatography- technique of separating different pigments based on chemical properties

22. 5. Observes radioactive compounds using “radioautography” • Technique that allows radioactive carbon to become visible. • By freezing photosynthesis at different times, Calvin was able to trace how carbon dioxide was converted to sugar.

23. AIM: What did Calvin discover?

24. Results of Calvin’s Experiment

25. Glycolysis

26. Calvin Cycle: A STEP A: Six carbon dioxide molecules enter the cycle from the atmosphere. The carbon dioxide molecules combine with six 5-carbon molecules. They rearrange to form 3 carbon molecules.

27. Step B: Energy investment stage • The 12 3 carbon molecules are then converted into higher energy forms. The energy for this conversion comes from ATP and NADPH • Where does the ATP and NADPH come from?

28. STEP C: Two of the twelve 3-carbon molecules rearrange into two similar 3 carbon molecules (PGAL)

29. Sheesh! That’s a lot of biochem.. • Let’s summarize: How many CO2 are needed to synthesize 1 glucose? How many ATP are needed to synthesize 1 glucose? How many NADPH are needed to synthesize 1 glucose?

30. Calvin Cycle • Energy input • Plants use energy that ATP and NADPH

31. Do Now: • Take out homework • Calvin Cycle Review How many: CO2 = 6 ATP= 18 ATP NADPH= 12 NADPH http://www.youtube.com/watch?v=_NIhg1qa_L0

32. AIM: Why did the plant die?

33. Hypothesis: If the plant dies, then Photosynthesis is not occurring

34. Materials: Benedict’s Solution and Lugol’s Solution • Indicators for glucose and starch

35. Factors that may affect photosynthesis: • Sunlight • Water • CO2 • Nutrients in the soil • Temperature

36. Plants can still produce glucose for a short time in the dark…. Why? • However, Plants need NADPH and ATP from the Light- Dependent reactions to continue photosynthesis

37. Rainforest Desert • Large, broad leaves Small, needlike leaves Cuticle covering

38. How can temperature affect photosynthesis? Enzymes in Photosynthesis work best between 0 and 35 degrees Celsius, after 35 Celsius, enzymes denature

39. How will carbon dioxide affect photosynthesis? • Carbon Dioxide is necessary during the Calvin Cycle to produce glucose

40. How will water affect photosynthesis?

41. How will water be transported to the top of trees?

42. Root Pressure • Concentration of nutrients and sugar is higher inside the roots than outside the plant… Water will move via Osmosis into the roots

43. Cohesion-Adhesion • Cohesion: water Molecules attract to One another • Adhesion: water Attracts to other sub- Stances • Cohesion and Adhesion lead to capillary action- tendency for water to rise in a thin tube

44. Transpirational Pull- water moves into the leaves via osmosis Transpiration: loss of water through the leaves Root pressure, capillary action, and transpirational pull contribute to the movement of water within a plant

45. Wilting • Too little water decreases TURGOR pressure in a plant, causing it to wilt

46. Summary: What may be wrong with Ms. Simon’s plant?