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PHOTOSYNTHESIS

Photosynthesis is an anabolic, endergonic process utilizing light energy to produce glucose in plants, bacteria, and protists. Explore the mechanisms and impacts of this vital biochemical process.

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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: Bozeman Science (Photosynthesis) http://www.bozemanscience.com/photosynthesis/ http://www.mhhe.com/biosci/bio_animations/02_MH_Photosynthesis_Web/index.html https://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120072/bio13.swf::Photosynthetic%20Electron%20Transport%20and%20ATP%20Synthesis Light Reactions of Photosynthesis: https://www.youtube.com/watch?v=BK_cjd6Evcw Calvin Cycle: https://highered.mheducation.com/sites/9834092339/student_view0/chapter39/calvin_cycle.html https://www.youtube.com/watch?v=sQK3Yr4Sc_k Photosynthesis (Khan Academy): https://www.youtube.com/watch?v=-rsYk4eCKnA Light Reactions 1 (Khan Academy): https://www.youtube.com/watch?v=GR2GA7chA_c Calvin Cycle (Khan Academy): https://www.youtube.com/watch?v=slm6D2VEXYs 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:https://www.youtube.com/watch?v=BK_cjd6EvcwPhotophosphorylation: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://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter8/calvin_cycle.html

  6. Photosynthesis Animations: Bozeman Science (Photosynthesis) http://www.bozemanscience.com/photosynthesis/ http://www.mhhe.com/biosci/bio_animations/02_MH_Photosynthesis_Web/index.html https://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120072/bio13.swf::Photosynthetic%20Electron%20Transport%20and%20ATP%20Synthesis Light Reactions of Photosynthesis: https://www.youtube.com/watch?v=BK_cjd6Evcw Calvin Cycle: https://highered.mheducation.com/sites/9834092339/student_view0/chapter39/calvin_cycle.html Crash Course (Photosynthesis): https://www.youtube.com/watch?v=sQK3Yr4Sc_k Photosynthesis (Khan Academy): https://www.youtube.com/watch?v=-rsYk4eCKnA Light Reactions 1 (Khan Academy): https://www.youtube.com/watch?v=GR2GA7chA_c Calvin Cycle (Khan Academy): https://www.youtube.com/watch?v=slm6D2VEXYs

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

  8. 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.

  9. Stomata Regulate Gas Exchange

  10. Leaf Anatomy

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

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

  13. Thylakoid Membrane Thylakoid Space Granum Thylakoids

  14. Nucleus Cell Wall Chloroplast Central Vacuole Mesophyll Cell

  15. Question: • Why are plants green?

  16. 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.

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

  18. Location and Structure of Chlorophyll Molecules in Plants

  19. 400 500 600 700 Short wave Long wave (more energy) (less energy) Wavelength of Light(nm)

  20. The Electromagnetic Spectrum

  21. violetbluegreenyelloworangered Absorption of Chlorophyll Absorption wavelength

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

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

  24. 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.

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

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

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

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

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

  30. 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.

  31. 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).

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

  33. 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

  34. 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

  35. How a Photosystem Harvests Light

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

  37. Cyclic Electron Flow

  38. 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

  39. 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

  40. 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

  41. 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)

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

  43. 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.

  44. Stroma Outer Membrane Thylakoid Granum Inner Membrane Chloroplast

  45. 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

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

  47. Comparison of chemiosmosis in mitochondria and chloroplasts

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