1. Photosynthesis Overview video 3 mins Overview video 3 mins

2. Photosynthesis over view  Carbon Dioxide + Water + SUNLIGHT  Sugar + Oxygen  CO 2 + H 2 O + SUN  C 6 H 12 O 6 + O 2

3. Photosynthesis occurs in the chloroplasts

4. Photosynthesis animation

5. Thylakoids – Structures inside chloroplasts where process of photosynthesis takes place

6. There are 2 basic steps for photosynthesis  1) Light reactions  2) Dark reactions (light independent reactions) Calvin cycle

7. MAIN FUNCTIONS of the 2 reactions  Light reactions convert light energy to temporary chemical energy (ATP & NADPH)  Dark reactions (Calvin Cycle) turn these chemical energy molecules into Sugars

8. Light reactions Occur in the Thylakoid membrane  Have two parts Photosystem II (PSII) Photosystem I (PSI)

9. Photosystem II (comes first) 3 STEPS 1) Sunlight hits Chlorophyll A and transfers energy to the reaction center (another Chlorophyll molecule) This releases electrons to the primary electron acceptor

10. Photosystem II 2) Electrons then travel through proein molecules in the electron transport chain (ETC) to PSI PS II PS I

11. Photosystem II 3) An enzyme splits water into protons, electrons and oxygen. This provides more electrons to travel to PSI

12. PSII

13. Water reaction in PSII 2H 2 0  4 H + + 4 e - + O 2 Protons (H + ) Will be used later in PSI Electrons (e - ) – Move along ETC to PSI Oxygen (O 2 ) – Released as a gas, NOT needed

14. Animation of photosystem II  http://vcell.ndsu.edu/animations/photosys temII/light.htm http://vcell.ndsu.edu/animations/photosys temII/light.htm http://vcell.ndsu.edu/animations/photosys temII/light.htm

15. Photosystem I (comes 2 nd ) 1)Electrons from ETC reach PSI reaction center in a second molecule of Chlorophyll A

16. Photosystem I 2) Sun helps electrons go through a 2 nd Electron transport chain (ETC) in membrane and turns NADP+ into NADPH

17. Photosystem I 3) ATP synthase pushes protons (H + ) out of membrane to make ATP H+

18. Overview

19. Reduction of NADPH  NADP + is reduced by electrons and protons that were produced by the water splitting  NADP + + e - + H +  NADPH

20. Formation of ATP The enzyme ATP synthase uses H + energy to produce ATP ADP + P + Energy  ATP

21. Animation – light dependant reaction  http://www.biology4all.com/resources_libr ary/source/61a.swf http://www.biology4all.com/resources_libr ary/source/61a.swf http://www.biology4all.com/resources_libr ary/source/61a.swf

22. Summary of light reactions  H 2 0 + sunlight + NADP + + ADP  O 2 + NADPH + ATP  The energy molecules NADPH and ATP can not be stored for long.  They will be used in Dark reactions to make sugar

23. Dark reactions (Calvin Cycle)  Occurs in Stroma  Called Light independent reactions  They do not need light, but they need the ATP and NADPH from the light reactions

24. Calvin Cycle in Dark  If there is no light, The Calvin Cycle soon uses up its ATP and NADPH and stops working.  LIKE a car, will drive for a while, but must fill up sometime

25. Calvin cycle = dark reactions = light independent reactions

26. Calvin Cycle overview  The process of using ATP and NADPH energy to join CO 2 into sugars

27. Calvin Cycle Steps 1) Carbon Fixation A molecule of CO 2 combines with RuBP (enzyme = Rubisco) then splits into 2 PGA molecules

28. Calvin Cycle Steps (C 3 ) 2) Reduction - ATP and NADPH used to form GP3, 3 carbon sugar

29. Calvin Cycle Steps (C 3 ) 3) Regeneration of RuBP - 5 of the 6 Carbons reform into RuBP

30. Production of sugar (C 3 Plants) Three turns of the cycle produce one 3 carbon sugar. 6 turns forms 1 glucose

32. What happens to the 3 carbon sugar?  Forms Glucose  Forms Sucrose  Forms Starches  Forms amino acids using Nitrogen

33. Summary of Dark Reactions  CO 2 + NADPH + ATP  Sugar + NADP + + ADP + P

34.  Why Light dependant?  The dark reactions are called the light dependant reactions because they depend on the ATP and NADPH produced in the light reactions