1. 1 Photosynthesis Energy & Life copyright cmassengale

2. 2 The Photosynthesis Equation copyright cmassengale

3. Redox Reactions copyright cmassengale3

4. 4 Redox Reaction The transfer of one or more electrons from one reactant to another Two types: 1.Oxidation is the loss of e - 2.Reduction is the gain of e -

5. 5 Oxidation Reaction The loss of electrons from a substance or the gain of oxygen. Example: Burning “Breaking Down Compounds”

6. 6 Reduction Reaction The gain of electrons to a substance or the loss of oxygen. “Building Up Compounds” Question: If electrons are gained, what happens to the CHARGE of the molecule?

7. Would photosynthesis be considered an oxidation reaction or a reduction reaction? Why? copyright cmassengale7

8. Photosynthesis Photosynthesis is the REDUCTION of Carbon Dioxide (CO 2 ) into Glucose (C 6 H 12 O 6 ) copyright cmassengale8 6CO 2 + 6H 2 O  6O 2 + C 6 H 12 O 6 Reduction

9. PHOTOSYNTHESIS The Reactions

10. 10 Photosynthesis Anabolic (small molecules combined) consume energy to build molecules from simpler onesAnabolic (small molecules combined) consume energy to build molecules from simpler ones Endergonic (stores energy)absorbs free energy from its surroundingsEndergonic (stores energy)absorbs free energy from its surroundings Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce organic macromolecules (glucose).Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce organic macromolecules (glucose). 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 glucose SUN photons

11. Electron Carriers Electron carriers are molecules that will “pick up” one or two hydrogen ions and electrons and carry them to another location. Examples: Photosynthesis = NADP + Cellular Respiration = NAD + & FAD + copyright cmassengale11

12. 12 Photosynthesis Overview copyright cmassengale

13. 1 st Step of Photosynthesis Light-Dependent ReactionsLight-Dependent Reactions –Requires light (Energy Source) –Occurs in the Thylakoids In the Chlorophyll (inside the Thylakoids) Across the Membrane of the Thylakoids

14. Light-Dependent Reactions These reactions use water molecules to produce oxygen gas. They use energy from light to produce ATP and NADPH (an electron carrier). They convert –ADP into ATP –NADP + into NADPH

15. Light-Dependent Big Idea Light is absorbed by chlorophyll to split water molecules and give off oxygen. This “charges up” the energy molecules ATP and NADPH.

16. 2 nd Step of Photosynthesis Calvin CycleCalvin Cycle –a.k.a. Light-Independent Reactions or Carbon Fixation –Does NOT require light Uses Energy Storage Molecules (ATP & NADPH) –Occurs in the Stroma copyright cmassengale16

17. Calvin Cycle (Light-Independent Reactions) Uses CO 2 and the “Left-over” Hydrogen from NADPH. Produces Glucose (C 6 H 12 O 6 ). These reactions use the ATP and NADPH produced in the light- dependent reactions to produce high-energy sugars.

18. Calvin Cycle Big Idea (Light-Independent) Energy is used from ATP and NADPH. The “left-over” hydrogens from the water are carried to the stroma by NADPH. They are combined with CO 2 to make glucose.

19. Light DependentCalvin Cycle Energy Source= Light Occurs in the Thylakoids (Chlorophyll & membranes) Changes ADP into ATP Changes NADP into NADPH Uses H 2 O Produces Oxygen Gas Energy Source = ATP and NADPH Occurs in the Stroma Changes ATP into ADP Changes NADPH into NADP Uses CO 2 & “left-over” H from NADPH Produces Glucose

20. 20 Photosynthesis Overview copyright cmassengale

21. Light Dependent Reaction copyright cmassengale21

22. 22 Thylakoid membranes Light Dependent reactions occur hereLight Dependent reactions occur here Photosystems are made up of clusters of chlorophyll molecules integrated into the thylakoid membranePhotosystems are made up of clusters of chlorophyll molecules integrated into the thylakoid membrane The two photosystems are:The two photosystems are: Photosytem I & Photosystem II Photosytem I & Photosystem II copyright cmassengale

23. 23 Occurs across the thylakoid membranesOccurs across the thylakoid membranes Uses light energyUses light energy Produce Oxygen from waterProduce Oxygen from water Convert ADP to ATPConvert ADP to ATP Also convert NADP + into the energy carrier NADPHAlso convert NADP + into the energy carrier NADPH Light Dependent Reactions copyright cmassengale

24. 24 Light Dependent Reaction copyright cmassengale

25. 25 Light Dependent Reaction copyright cmassengale

26. 26 Photosystem II Discovered Second but OCCURS FIRSTDiscovered Second but OCCURS FIRST Contains about equal amounts of chlorophyll a and chlorophyll bContains about equal amounts of chlorophyll a and chlorophyll b Photosystem II absorbs light energyPhotosystem II absorbs light energy SPLITS H 2 O into O 2SPLITS H 2 O into O 2 Excites Electrons!Excites Electrons! copyright cmassengale

27. 27 Photosynthesis Begins Electrons are energized and passed to the Electron Transport Chain Lost electrons are replaced from the splitting of water into 2H +, free electrons, and Oxygen 2H + pumped across thylakoid membrane (active transport) copyright cmassengale

28. 28 Noncyclic Electron Flow P700 Photosystem I P680 Photosystem II Primary Electron Acceptor ETC H 2 O 1/2O 2 1/2O 2 + 2H + ATP Photon 2e - SUN H 2 O is split in PSII & ATP is made

29. 29 Photosystem I Discovered First but occurs SECONDDiscovered First but occurs SECOND Almost completely chlorophyll aAlmost completely chlorophyll a MAKES NADPHMAKES NADPH copyright cmassengale

30. 30 Photosystem I High-energy electrons are moved to Photosystem I through the Electron Transport ChainHigh-energy electrons are moved to Photosystem I through the Electron Transport Chain Energy is used to transport H + from stroma to inner thylakoid membraneEnergy is used to transport H + from stroma to inner thylakoid membrane NADP+ converted to NADPH when it picks up 2 electrons & H+NADP+ converted to NADPH when it picks up 2 electrons & H+ copyright cmassengale

31. 31 Noncyclic Electron Flow P700 Photosystem I P680 Photosystem II Primary Electron Acceptor Primary Electron Acceptor ETC Enzyme Reaction H 2 O 1/2O 2 1/2O 2 + 2H + ATP NADPH Photon 2e - SUN Photon The energy carrier NADPH is made in PSI

32. 32 Noncyclic Electron Flow ADP +  ATPADP +  ATP NADP + + H  NADPHNADP + + H  NADPH Oxygen comes from the splitting of H 2 O, not CO 2Oxygen comes from the splitting of H 2 O, not CO 2 H 2 O  1/2 O 2 + 2H + H 2 O  1/2 O 2 + 2H + P

33. 33 Chemiosmosis

34. 34 Chemiosmosis Powers ATP synthesisPowers ATP synthesis Takes place across the thylakoid membraneTakes place across the thylakoid membrane Uses ETC and ATP synthase (enzyme)Uses ETC and ATP synthase (enzyme) H+ move down their concentration gradient through channels of ATP synthase forming ATP from ADPH+ move down their concentration gradient through channels of ATP synthase forming ATP from ADP

35. 35copyright cmassengale

36. 36 Light Reaction Summary Reactant: H 2 O Also Needed: Light Energy, Chlorophyll, ADP & NADP Products: O 2 (PS II; released into atmosphere)O 2 (PS II; released into atmosphere) ATP (chemiosmosis)ATP (chemiosmosis) NADPH (PS I; used in the Calvin Cycle)NADPH (PS I; used in the Calvin Cycle) copyright cmassengale

37. Light Dependent Reaction Simulation http://www.youtube.com/watc h?v=RFl25vSElaEhttp://www.youtube.com/watc h?v=RFl25vSElaE Video http://www.youtube.com/watch?v=v590JJV96lc http://www.youtube.com/watch?v=v590JJV96lc Rap http://www.youtube.com/watch?v=pE82qtKSSH4 http://www.youtube.com/watch?v=pE82qtKSSH4 Light Dependent Claymation http://www.youtube.com/watch?v=CLf4yu8Iwo0 http://www.youtube.com/watch?v=CLf4yu8Iwo0 copyright cmassengale37

38. The Calvin Cycle copyright cmassengale38

39. REMEMBER The following were produced during the Light-Dependent Reaction: –O 2 (released into the atmosphere) ENERGY –NAPDH & ATP (used for ENERGY in the Calvin Cycle) copyright cmassengale39

40. 40 2 nd Step of Photosynthesis Calvin Cycle aka Light Independent Reaction, Dark Reaction, Carbon Fixation or C 3 Fixationaka Light Independent Reaction, Dark Reaction, Carbon Fixation or C 3 Fixation Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).Uses energy (ATP and NADPH) from light reaction to make sugar (glucose). Occurs in the stromaOccurs in the stroma Uses 6 CO 2Uses 6 CO 2

41. 41 Chloroplast Granum Thylakoid STROMA– where Calvin Cycle occurs Outer Membrane Inner Membrane

42. Calvin Cycle RuBP (a 5-carbon sugar) attaches to each CO 2 forming a temporary 6-carbon sugarRuBP (a 5-carbon sugar) attaches to each CO 2 forming a temporary 6-carbon sugar This 6-carbon sugar splits apart into 2 3-carbon sugars called PGAThis 6-carbon sugar splits apart into 2 3-carbon sugars called PGA PGA exchanges Hydrogen and Oxygen to transform into G 3 Ps (a different 3-carbon sugar)PGA exchanges Hydrogen and Oxygen to transform into G 3 Ps (a different 3-carbon sugar) copyright cmassengale42

43. Calvin Cycle (continued) 2 G 3 Ps combine to form Glucose (C 6 H 12 O 6 )2 G 3 Ps combine to form Glucose (C 6 H 12 O 6 ) The other G 3 Ps combine to become RuBP moleculesThe other G 3 Ps combine to become RuBP molecules To produce 1 Glucose moleculeTo produce 1 Glucose molecule –6 turns of the cycle –Uses 18 ATP and 12 NADPH –“Fixes” 6 CO 2 molecules into a usable form for organisms copyright cmassengale43

44. 44 Calvin Cycle (C 3 fixation) 6CO 2 6C-C-C-C-C-C 6C-C-C 6C-C-C-C-C 12PGA RuBP 12G 3 P (unstable) 6NADPH 6ATP C-C-C-C-C-C Glucose (6C) (36C) (30C) (6C) 6C-C-C C3C3 glucose

45. 45 Calvin Cycle Remember: C 3 = Calvin Cycle C3C3 Glucose 6 CO 2 “fixed” Glucose (C 6 H 12 O 6 ) Big Idea: 6 CO 2 molecules are “fixed” into Glucose (C 6 H 12 O 6 ) ADP & NADP+ are reused in the next light-dependent reaction

46. More Videos Calvin Cycle Claymation https://www.youtube.com/watch?v=hhkpJwSDxQQ https://www.youtube.com/watch?v=hhkpJwSDxQQ Calvin Cycle Animation https://www.youtube.com/watch?v=E_XQR800AgM https://www.youtube.com/watch?v=E_XQR800AgM Crash Course Biology: Photosynthesis https://www.youtube.com/watch?v=sQK3Yr4Sc_k https://www.youtube.com/watch?v=sQK3Yr4Sc_k copyright cmassengale46

47. How do these large trees get all their mass? Complete the Life Science Assessment Probe – Giant Sequoia Tree