20100906140910 presentation1 photosynthesis


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20100906140910 presentation1 photosynthesis

  1. 2. What are the process occurs in photosynthesis? How starch is synthesize?
  2. 3. THYLAKOID Chloroplast Dark reaction occurs Light reaction occurs STROMA
  3. 4. <ul><li>Light Reaction </li></ul><ul><li>Light energy Chemical energy </li></ul><ul><li>Chlorophyll & accessory pigments absorb slightly different color of light and pass its energy to central chlorophyll molecule (Chlorophyll a) to do photosynthesis. </li></ul><ul><li>Two forms of chlorophyll a molecules </li></ul><ul><li>P700 in PSI (700 nm) </li></ul><ul><li>P680 in PSII(680 nm) </li></ul><ul><li>Role of Photosystem </li></ul><ul><li>:Provide sufficient energy to boost the photoactivated electron to an energy level high enough accepted by NADP </li></ul><ul><li>: pump proton across thylakoid membranes. </li></ul>
  4. 5. Non-cyclic photophosphorylation
  5. 6. Cyclic Photophosphorylation
  6. 7. Photosynthesis: Pathway of Carbon Fixation STARCH
  7. 9. CO2 combines with the phosphorylated 5-carbon sugar ribulose bisphosphate (RUBP) reaction is catalyzed by the enzyme ribulose bisphosphate carboxylase oxygenase ( RUBISCO ) resulting 6-carbon compound breaks down into two molecules of 3-phosphoglyceric acid ( PGA ). PGA molecules are further phosphorylated (by ATP ) and are reduced (by NADPH ) to form phosphoglyceraldehyde ( PGAL ). Enzyme responsible for fixing 200 bilion tons of CO2 anually
  8. 10. Phosphoglyceraldehyde (PGAL) serves as the starting material for the synthesis of glucose and fructose . Glucose and fructose PolysaccharideSynthesis starch & cellulose Travel to other part of the plant As Monomer Sucrose
  9. 11. CO2 + H20 3-phosphoglycerate ATP + NADPH ADP + Pi NADP+ Triose Phosphate Sucrose, Starch ATP ADP CARBOXYLATION REDUCTION REGENERATION
  10. 12. Equation of sugar glucose <ul><li>6CO2 + 12H2O  C6H12O6 + 6H2O + 6O2 </li></ul>
  11. 13. CH2O~P Chlorophyll H20 O2 CH2O~P H20 CO2 + H2O ( CH2O)n ATP [ADP + Pi], NADP+ + NADPH Light
  12. 14. Reduction Process in Calvin cycle
  13. 15. <ul><li>Adds a phosphate from ATP to the 3-PGA </li></ul><ul><li>removes hydrogen from NADPH and adds it to the 1,3-bisphosphoglycerate </li></ul><ul><li>In this reduction, a phosphate is removed </li></ul><ul><li>resulting NADP+, ADP, and Pi can be recycled to the light reactions </li></ul><ul><li>These steps demonstrate why the light reactions and Calvin cycle are interdependent </li></ul>
  14. 16. Why convert Glucose to Starch?
  15. 17. <ul><li>products of photosynthesis are assembled in plant to make glucose </li></ul><ul><li>Glucose (C 6 H 12 O 6 ) is a monosaccharide or single sugar </li></ul><ul><li>plant uses glucose as short-term energy storage </li></ul><ul><li>converted into a polysaccharide called starch, allowing the plant to store most of the energy collected in photosynthesis in the chemical bonds between the sugars </li></ul>
  16. 18. <ul><li>When the plant needs energy, the bonds holding the glucose molecules together are broken, and energy is released </li></ul><ul><li>Starch is a better way to store energy because it has more bonds to hold potential energy and it can be stored in large amounts without disturbing the rest of the plant. </li></ul>