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PHOTOSYNTHESIS

PHOTOSYNTHESIS. SUN. photons. glucose. Photosynthesis. An anabolic , endergonic , 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. Question:.

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PHOTOSYNTHESIS

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  1. PHOTOSYNTHESIS

  2. SUN photons glucose Photosynthesis • An anabolic, endergonic, carbondioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose). 6CO2 + 6H2O  C6H12O6 + 6O2

  3. Question: • In what types of organisms does photosynthesis take place?

  4. In plants, bacteria, and protists

  5. Photosynthesis Animations Comprehensive Overview: http://www.wiley.com/college/test/0471787159/biology_basics/animations/photosynthesis.html Cyclic and Noncyclic Photophosphorylation:http://highered.mcgraw-hill.com/olc/dl/120072/bio12.swfElectron Transport Chain:http://highered.mcgraw-hill.com/olc/dl/120072/bio13.swfLight Reactions:http://www.biologyalive.com/life/classes/apbiology/documents/Unit%207/10_Lectures_PPT/media/10_17LightReactions_A.swfPhotophosphorylation:http://bcs.whfreeman.com/thelifewire/content/chp08/0802002.html Proton Pumps: http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter5/proton_pump.htmlCalvin Cycle:http://www.biologyalive.com/life/classes/apbiology/documents/Unit%207/10_Lectures_PPT/media/10_18CalvinCycle_A.swfCalvin Cycle:http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter8/calvin_cycle.html

  6. Chloroplast Mesophyll Cell Stoma Plants • Autotrophs:self-producers. • Location: 1. Leaves a. stoma b. mesophyll cells

  7. Oxygen (O2) Carbon Dioxide (CO2) Guard Cell Guard Cell Stomata • Poresin a plant’s cuticle through which water and gases are exchanged between the plant and the atmosphere.

  8. Stomata Regulate Gas Exchange

  9. Leaf Anatomy

  10. Stroma Outer Membrane Thylakoid Granum Inner Membrane Chloroplast • Organelle where photosynthesis takes place.

  11. Mesophyll Chloroplast 5 µm Outer membrane Thylakoid Intermembrane space Thylakoid space Granum Stroma Inner membrane 1 µm • Chloroplasts • Contain thylakoids and grana

  12. Thylakoid Membrane Thylakoid Space Granum Thylakoids

  13. Nucleus Cell Wall Chloroplast Central Vacuole Mesophyll Cell

  14. Question: • Why are plants green?

  15. Chlorophyll Molecules • Located in the thylakoid membranes. • Chlorophyll have Mg+ in the center. • Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red-660nm are most important). • Plants are green because the green wavelength is reflected, not absorbed.

  16. Why leaves are green: interaction of light with chloroplasts

  17. Location and Structure of Chlorophyll Molecules in Plants

  18. 400 500 600 700 Short wave Long wave (more energy) (less energy) Wavelength of Light(nm)

  19. The Electromagnetic Spectrum

  20. violetbluegreenyelloworangered Absorption of Chlorophyll Absorption wavelength

  21. Evidence that chloroplast pigments participate in photosynthesis: absorption and action spectra for photosynthesis in an alga

  22. Question: • During the fall, what causes the leaves to change colors?

  23. Fall Colors • In addition to the chlorophyll pigments, there are other pigments present. • During the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments. • Carotenoids are pigments that are either red or yellow.

  24. Redox Reaction • The transfer of one or more electrons from one reactant to another. • Two types: 1. Oxidation 2. Reduction

  25. Oxidation 6CO2 + 6H2O  C6H12O6 + 6O2 glucose Oxidation Reaction • The loss of electrons from a substance. • Or the gain of oxygen.

  26. Reduction 6CO2 + 6H2O  C6H12O6 + 6O2 glucose Reduction Reaction • The gain of electrons to a substance. • Or the loss of oxygen.

  27. Oxidation (releases energy) • Combining with Oxygen • Loss of Electrons • Loss of Hydrogen • Reduction (absorbs energy) • Separation from Oxygen • Gain of Electrons • Gain of Hydrogen

  28. Remember: “Leo says Ger” Loss of electrons is oxidation; Gain of electrons is reduction. or “Oil Rig” Oxidation is loss; Reduction is gain.

  29. Breakdown of Photosynthesis • Two main parts (reactions). 1. Light Reaction or Light Dependent Reaction Produces energy from solarpower(photons) in the form of ATP and NADPH.

  30. Breakdown of Photosynthesis 2. Calvin Cycle or Light Independent Reaction or Carbon Fixation or C3 Fixation Uses energy(ATP and NADPH) from light rxn to make sugar (glucose).

  31. An Overview of Photosynthesis: Cooperation of the Light Reactions and the Calvin Cycle

  32. 1. Light Reaction (Electron Flow) • Occurs in the thylakoid membranes • During the light reaction, there are two possible routes for electron flow. A. Cyclic Electron Flow B. Noncyclic Electron Flow

  33. P A. Cyclic Electron Flow • Occurs in the thylakoid membrane. • Uses Photosystem I only • P700 reaction center- chlorophyll a • Uses Electron Transport Chain (ETC) • Generates ATP only ADP + ATP

  34. How a Photosystem Harvests Light

  35. e- Primary Electron Acceptor SUN e- ATP produced by ETC e- Photons e- P700 Accessory Pigments Photosystem I A. Cyclic Electron Flow

  36. Cyclic Electron Flow

  37. B. Noncyclic Electron Flow • Occurs in the thylakoid membrane • Uses PS II and PS I • P680 rxn center (PSII) - chlorophyll a • P700 rxn center (PS I) - chlorophyll a • Uses Electron Transport Chain (ETC) • Generates O2, ATP and NADPH

  38. H2O CO2 Light NADP+ ADP CALVIN CYCLE LIGHT REACTIONS ATP NADPH Electron Transport chain O2 [CH2O] (sugar) Primary acceptor 7 Primary acceptor 4 Fd Electron transport chain Pq 2 8 e e– e H2O NADP+ + 2 H+ Cytochrome complex 2 H+ NADP+ reductase + 3 NADPH O2 PC e– + H+ 5 P700 e– Light P680 Light 1 6 ATP Photosystem-I (PS I) Photosystem II (PS II) Figure 10.13 • Produces NADPH, ATP, and oxygen

  39. Primary Electron Acceptor 2e- Enzyme Reaction Primary Electron Acceptor 2e- 2e- ETC 2e- SUN 2e- NADPH P700 Photon ATP P680 Photon H2O 1/2O2+ 2H+ Photosystem I Photosystem II B. Noncyclic Electron Flow

  40. P (Reduced) B. Noncyclic Electron Flow • ADP + ATP • NADP+ + H NADPH • Oxygen comes from the splitting of H2O, not CO2 H2O  1/2 O2 + 2H+ (Reduced) (Oxidized)

  41. How Noncyclic Electron Flow During the Light Reactions Generates ATP and NADPH

  42. Chemiosmosis • Powers ATP synthesis. • Located in the thylakoid membranes. • Uses ETC and ATP synthase(enzyme) to make ATP. • Photophosphorylation: addition of phosphate to ADP to make ATP.

  43. Stroma Outer Membrane Thylakoid Granum Inner Membrane Chloroplast

  44. SUN (Proton Pumping) H+ H+ Thylakoid E T PS I PS II C high H+ concentration H+ H+ H+ H+ H+ H+ Thylakoid Space H+ ATP Synthase low H+ concentration ADP + P ATP H+ Chemiosmosis

  45. The light reactions and chemiosmosis: the organization of the thylakoid membrane

  46. Comparison of chemiosmosis in mitochondria and chloroplasts

  47. Calvin Cycle • Carbon Fixation (light independent rxn). • C3 plants (80% of plants on earth). • Occurs in the stroma. • Uses ATP and NADPH from light rxn and also uses CO2 from air. • To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.

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