1. The overall equation for the cellular respiration of glucose is A) C 5 H 12 O 6 + 6 O 2 → 5 CO 2 + 6 H 2 O + energy. B) 5 CO2 + 6 H 2 O → C 5 H 12 O 6 + 6 O 2 + energy. C) C 6 H 12 O 12 + 3 O 2 → 6 CO 2 + 6 H 2 O + energy. D) C 6 H 12 O 6 + 6 O 2 → 6 CO 2 + 6H 2 2O + energy. E) None of the choices are correct.

2. Photosynthesis

3. Review Describe the environment inside different areas in the mitochondria. What is the purpose of the electron transport chain? What is the purpose of the Krebs cycle?

4. Photosynthesis is the process on which nearly all life depends

5. Photosynthesis is the opposite of respiration

6. Photosynthesis completes the carbon cycle

7. Photosynthesis counteracts the greenhouse effect

8. C 6 H 12 O 6(s) + 6O 2(g)  6CO 2(g) + 6H 2 O (l) + energy This is a combustion reaction Combustion is a kind of redox reaction Energy in presence of oxygen: ~38 ATP Aerobic respiration of glucose is the most basic means for cells to acquire energy

9. 6CO 2(g) + 6H 2 O (l) + energy  C 6 H 12 O 6(s) + 6O 2(g) carb. Diox.+H 2 O+ sunlight  glucose+oxygen… This is still a redox reaction What is oxidized? What is reduced? Photosynthesis can be thought of as the opposite of respiration

10. Figure 7.4A

11. Photosynthesis is the manufacture of food using energy from the sun The site of photosynthesis is the chloroplast, which occurs in plant cells Chloroplasts have their own DNA, and a double bilayer system as do mitochondria

12. Photosynthesis has a few similarities with respiration Metabolic cycles Redox molecules (NADP + instead of NAD+ and FAD) ATP generation Specialized organelles (chloroplasts instead of mitochondria)

13. Chloroplast structure Double bilayer Grana made of Thylakoid membranes Stroma is the liquid in which the grana sit Photosynthesis occurs in chloroplasts in two stages- light reactions and dark

14. LE 10-3 Leaf cross section Vein Mesophyll Stomata CO 2 O2O2 Mesophyll cell Chloroplast 5 µm Outer membrane Intermembrane space Inner membrane Thylakoid space Thylakoid GranumStroma 1 µm

15. Where does the oxygen come from, H 2 O or CO 2 ? 6CO 2(g) + 6H 2 O (l) + h ν  C 6 H 12 O 6(s) + 6O 2(g)

16. There are 2 major stages of photosynthesis Light-dependent reactions (“Light reactions”) Light-independent reactions (“Dark reactions”)

17. Light and Dark reactions Light-dependent reactions –Water is split –ATP is formed –O2 is evolved Light-independent reactions –Carbon is fixed –Electrons and ATP are consumed –Glucose precursor (G3P) is formed

18. LE 10-5_1 H2OH2O LIGHT REACTIONS Chloroplast Light

19. LE 10-5_2 H2OH2O LIGHT REACTIONS Chloroplast Light ATP NADPH O2O2

20. LE 10-5_3 H2OH2O LIGHT REACTIONS Chloroplast Light ATP NADPH O2O2 NADP + CO 2 ADP P + i CALVIN CYCLE [CH 2 O] (sugar)

21. Light-dependent reactions depend on light (duh) Some details about light: Visible light is a small subset of the electro- magnetic spectrum 400-700nm Short wavelengths~ higher energy

22. Light can excite electrons in atoms

23. Chlorophyll is a light-absorbing pigment There are other light absorbing pigments Chlorophyll a and b exist Its absorption spectrum can be measured in vitro We measure light absorbance with a spectrophotometer

24. LE 10-9a Chlorophyll a Chlorophyll b Carotenoids Wavelength of light (nm) Absorption spectra- will these be the same in vivo? Absorption of light by chloroplast pigments 400 500600 700

25. LE 10-8a White light Refracting prism Chlorophyll solution Photoelectric tube Galvanometer The high transmittance (low absorption) reading indicates that chlorophyll absorbs very little green light. Green light Slit moves to pass light of selected wavelength 0 100

26. LE 10-8b White light Refracting prism Chlorophyll solution Photoelectric tube The low transmittance (high absorption) reading indicates that chlorophyll absorbs most blue light. Blue light Slit moves to pass light of selected wavelength 0 100

27. Chlorophyll is a fluorescent molecule It absorbs blue It re-emits red (It can also absorb red…)

28. Other pigments absorb different wavelengths Different pigments can cooperate to transfer energy

29. Leaves are nature’s solar panels

30. The light reactions Consisting of two photosystems, an electron transport chain, and ATP synthase

31. Photosystems There are two photosystems: 1)Photosystem II 2)Photosystem I A photosystem is… -A special chlorophyll molecule (p680/p700) -Other pigments -In a protein bundle, in the thylakoid membrane

32. There are two types of photosystems in the thylakoid membrane Photosystem II functions first (the numbers reflect order of discovery) and is best at absorbing a wavelength of 680 nm Photosystem I is best at absorbing a wavelength of 700 nm The two photosystems work together to use light energy to generate ATP and NADPH

33. LE 10-12 Thylakoid Photon Light-harvesting complexes Photosystem Reaction center STROMA Primary electron acceptor e–e– Transfer of energy Special chlorophyll a molecules Pigment molecules THYLAKOID SPACE (INTERIOR OF THYLAKOID) Thylakoid membrane Accessory pigments can be assembled with proteins into a membrane-bound photosystem At the center there is a reaction center Accessory pigments are a “photon transfer chain” (Resonance Energy Transfer)

34. LE 10-13_1 Light P680 e–e– Photosystem II (PS II) Primary acceptor [CH 2 O] (sugar) NADPH ATP ADP CALVIN CYCLE LIGHT REACTIONS NADP + Light H2OH2O CO 2 Energy of electrons O2O2

35. LE 10-13_2 Light P680 e–e– Photosystem II (PS II) Primary acceptor [CH 2 O] (sugar) NADPH ATP ADP CALVIN CYCLE LIGHT REACTIONS NADP + Light H2OH2O CO 2 Energy of electrons O2O2 e–e– e–e– + 2 H + H2OH2O O2O2 1/21/2 Photosystem II splits water Water is oxidized 2H 2 O  4H + +O 2

36. LE 10-13_3 Light P680 e–e– Photosystem II (PS II) Primary acceptor [CH 2 O] (sugar) NADPH ATP ADP CALVIN CYCLE LIGHT REACTIONS NADP + Light H2OH2O CO 2 Energy of electrons O2O2 e–e– e–e– + 2 H + H2OH2O O2O2 1/21/2 Pq Cytochrome complex Electron transport chain Pc ATP Photo- system II takes electrons from water and hands them to the e- transport chain

37. The electron transport chain makes a proton gradient..

38. ATP synthase uses the proton gradient to make ATP

39. Photosystem 1 hands e-’s to NADP + to make NADPH…

40. LE 10-13_4 Light P680 e–e– Photosystem II (PS II) Primary acceptor [CH 2 O] (sugar) NADPH ATP ADP CALVIN CYCLE LIGHT REACTIONS NADP + Light H2OH2O CO 2 Energy of electrons O2O2 e–e– e–e– + 2 H + H2OH2O O2O2 1/21/2 Pq Cytochrome complex Electron transport chain Pc ATP P700 e–e– Primary acceptor Photosystem I (PS I) Light

41. LE 10-13_5 Light P680 e–e– Photosystem II (PS II) Primary acceptor [CH 2 O] (sugar) NADPH ATP ADP CALVIN CYCLE LIGHT REACTIONS NADP + Light H2OH2O CO 2 Energy of electrons O2O2 e–e– e–e– + 2 H + H2OH2O O2O2 1/21/2 Pq Cytochrome complex Electron transport chain Pc ATP P700 e–e– Primary acceptor Photosystem I (PS I) e–e– e–e– Electron Transport chain NADP + reductase Fd NADP + NADPH + H + + 2 H + Light

42. …and the NADPH is used to turn CO2 into Glucose

43. LE 10-14 ATP Photosystem II e–e– e–e– e–e– e–e– Mill makes ATP e–e– e–e– e–e– Photon Photosystem I Photon NADPH

44. A Comparison of Chemiosmosis in Chloroplasts and Mitochondria Chloroplasts and mitochondria generate ATP by chemiosmosis, but use different sources of energy Mitochondria transfer chemical energy from food to ATP; chloroplasts transform light energy into the chemical energy of ATP The spatial organization of chemiosmosis differs in chloroplasts and mitochondria

45. LE 10-16 MITOCHONDRION STRUCTURE Intermembrane space Membrane Electron transport chain Mitochondrion Chloroplast CHLOROPLAST STRUCTURE Thylakoid space Stroma ATP Matrix ATP synthase Key H+H+ Diffusion ADP +P H+H+ i Higher [H + ] Lower [H + ]

46. LE 10-17 STROMA (Low H + concentration) Light Photosystem II Cytochrome complex 2 H + Light Photosystem I NADP + reductase Fd Pc Pq H2OH2O O2O2 +2 H + 1/21/2 2 H + NADP + + 2H + + H + NADPH To Calvin cycle THYLAKOID SPACE (High H + concentration) STROMA (Low H + concentration) Thylakoid membrane ATP synthase ATP ADP + P H+H+ i [CH 2 O] (sugar) O2O2 NADPH ATP ADP NADP + CO 2 H2OH2O LIGHT REACTIONS CALVIN CYCLE Light

47. The Calvin Cycle or, The Citric Acid cycle backward: ATP and electron carriers are used to reduce CO 2 to glucose

48. The Calvin cycle requires three ingredients: –Carbon dioxide (catalyzed by rubisco) –ATP –Electrons

49. RubisCO grabs CO2 from the air AKA Ribulose Bisphosphate Carboxylase Oxidase The carbon fixing enzyme The most common enzyme on the planet Adds 3CO2’s to 3 RuBP’s at a time

50. LE 10-18_1 [CH 2 O] (sugar) O2O2 NADPH ATP ADP NADP + CO 2 H2OH2O LIGHT REACTIONS CALVIN CYCLE Light Input 3 CO 2 (Entering one at a time) Rubisco 3 P P Short-lived intermediate Phase 1: Carbon fixation 6 P 3-Phosphoglycerate 6 ATP 6 ADP CALVIN CYCLE 3 P P Ribulose bisphosphate (RuBP) Step 1: Carbon Fixation

51. LE 10-18_2 [CH 2 O] (sugar) O2O2 NADPH ATP ADP NADP + CO 2 H2OH2O LIGHT REACTIONS CALVIN CYCLE Light Input CO 2 (Entering one at a time) Rubisco 3PP Short-lived intermediate Phase 1: Carbon fixation 6 P 3-Phosphoglycerate 6 ATP 6 ADP CALVIN CYCLE 3 PP Ribulose bisphosphate (RuBP) 3 6 NADP + 6 6 NADPH P i 6P 1,3-Bisphosphoglycerate P 6 P Glyceraldehyde-3-phosphate (G3P) P1 G3P (a sugar) Output Phase 2: Reduction Glucose and other organic compounds Each lap generates 1 G3P Radioactive CO 2 allows tracking of these molecules (with liquid N 2 )

52. LE 10-18_3 [CH 2 O] (sugar) O2O2 NADPH ATP ADP NADP + CO 2 H2OH2O LIGHT REACTIONS CALVIN CYCLE Light Input CO 2 (Entering one at a time) Rubisco 3PP Short-lived intermediate Phase 1: Carbon fixation 6 P 3-Phosphoglycerate 6 ATP 6 ADP CALVIN CYCLE 3 PP Ribulose bisphosphate (RuBP) 3 6 NADP + 6 6 NADPH P i 6P 1,3-Bisphosphoglycerate P 6 P Glyceraldehyde-3-phosphate (G3P) P1 G3P (a sugar) Output Phase 2: Reduction Glucose and other organic compounds 3 3 ADP ATP Phase 3: Regeneration of the CO 2 acceptor (RuBP) P 5 G3P

53. The Importance of Photosynthesis: A Review The energy entering chloroplasts as sunlight gets stored as chemical energy in organic compounds Sugar made in the chloroplasts supplies chemical energy and carbon skeletons to synthesize the organic molecules of cells In addition to food production, photosynthesis produces the oxygen in our atmosphere

54. LE 10-21 Light CO 2 H2OH2O Light reactionsCalvin cycle NADP + RuBP G3P ATP Photosystem II Electron transport chain Photosystem I O2O2 Chloroplast NADPH ADP +P i 3-Phosphoglycerate Starch (storage) Amino acids Fatty acids Sucrose (export)

55. Which of the following is not an example of a photoautotroph? A) cyanobacteria in freshwater and marine ecosystems B) kelp in an underwater forest C) herbs like thyme and basil D) fungi E) algae

56. The energy that excites P680 and P700 is supplied by A) electrons passing down the electron transport chain. B) the breaking of glucose bonds. C) ATP. D) photons. E) NADPH.