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Photosynthesis
<ul><li>LIFE ON EARTH ULTIMATELY DEPENDS ON ENERGY </li></ul>
So what is ENERGY? <ul><li>Some define it as the ability to  </li></ul><ul><li>work. </li></ul><ul><li>In physics the capa...
Energy can be transformed from one form to another
SOURCES OF ENERGY <ul><li>COAL </li></ul><ul><li>OIL </li></ul>
THE SUN: MAIN SOURCE OF ENERGY FOR LIFE ON EARTH
What is photosynthesis? <ul><li>The process that plants use to make their own food </li></ul><ul><li>Plants’ leaves contai...
<ul><li>THE GENERAL PROCESS </li></ul>
The chlorophyll absorbs the  sunlight .
The sunlight is combined with  water ,  Carbon Dioxide  and  nutrients  from the  soil . CO 2
The  chlorophyll  processes the ingredients and makes  sugar  (plant food) and oxygen. Sugar  + Air O 2
THE FORMULA <ul><li>6CO 2   +  6H 2 O     C 6 H 12 O 6   +  6O 2 </li></ul>glucose SUN
<ul><li>IN ECOLOGICAL PRINCIPLE….. </li></ul>
Plants and animals need each other to survive.
Animals including humans make the CO 2  (carbon dioxide) plants need. They (the plants) make the O 2  (oxygen) and food we...
<ul><li>LIFE ON EARTH ULTIMATELY DEPENDS ON ENERGY </li></ul>
The chlorophyll absorbs the  sunlight .
The  chlorophyll  processes the ingredients and makes  sugar  (plant food) and oxygen. Sugar  + Air O 2
<ul><li>THE PHYSICAL AND CHEMICAL PROCESS </li></ul>
Two Parts of Photosynthesis <ul><li>Two reactions make up photosynthesis: </li></ul><ul><li>1. Light Reaction or Light Dep...
Two Parts of Photosynthesis <ul><li>2.  Calvin Cycle or Light  Independent Reaction </li></ul><ul><li>Also called  Carbon ...
Redox Reaction <ul><li>The  transfer  of one or more  electrons  from one reactant to another </li></ul><ul><li>Two types:...
Reduction Reaction <ul><li>The  gain of electrons  to a substance or the  loss of oxygen. </li></ul>glucose 6CO 2   +  6H ...
Oxidation Reaction <ul><li>The  loss of electrons  from a substance or the  gain of oxygen. </li></ul>Carbon dioxide Water...
Question: <ul><li>Where does photosynthesis take place? </li></ul>
<ul><li>Mainly occurs in the  leaves: </li></ul><ul><li>a. stoma - pores </li></ul><ul><li>b. mesophyll cells </li></ul>St...
Stomata (stoma) <ul><li>Pores  in a plant’s cuticle through which  water vapor  and  gases   (CO 2  & O 2 )  are exchanged...
Mesophyll Cell of Leaf Photosynthesis occurs in these cells! Cell Wall Nucleus Chloroplast Central Vacuole
Chloroplast <ul><li>Organelle  where  photosynthesis   takes place. </li></ul>Thylakoid stacks are connected together Gran...
Thylakoid Grana make up the inner membrane Thylakoids contain chlorophylls Thylakoid Membrane Thylakoid Space Granum
<ul><li>The location and structure of chloroplasts overview </li></ul>LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast M...
LIGHT REACTION glucose 6CO 2   +  6H 2 O     C 6 H 12 O 6   +  6O 2 SUN
The chlorophyll absorbs the  sunlight .
PROPERTIES OF LIGHT <ul><li>Light has properties of both particles and wave </li></ul><ul><ul><li>Wave: is characterized b...
Absorption of Light by Chlorophyll wavelength Absorption Chlorophyll absorbs blue-violet & red light best violet   blue   ...
<ul><li>Chlorophyll (in its lowest energy/ground = Chl) absorbs a photon ( hv)  and makes a transition to a higher energy ...
Excited state e  Heat Light Photon Light (fluorescence) Chlorophyll molecule Ground state 2 (a) Absorption of a photon (b...
Wavelength of Light (nm) ABSOPRTION OF LIGHT EXCITES Chl INTO HIGHER ENERGY STATE WHEN PHOTONS HAVE SHORTER WAVELENGTH 400...
SPECIFIC SITE  OF ABSORPTION IN CHLOROPLAST <ul><li>Light is absorbed in the  integral membrane components   of the thylak...
<ul><li>Antenna complex </li></ul>SUN Reaction center Pigment molecules BASIC CONCEPT OF ENERGY TRANSFER DURING PHOTOSYNTH...
POSSIBLE ROUTES FOR ELECTRON FLOW <ul><li>Cylclic electron flow </li></ul><ul><li>Non-cyclic electron flow </li></ul>
Cyclic Electron Flow <ul><li>Occurs in the  thylakoid  membrane. </li></ul><ul><li>Uses  Photosystem I only </li></ul><ul>...
Cyclic Electron Flow Pigments absorb light energy & excite e- of Chlorophyll a to produce ATP  P700 Primary Electron Accep...
Noncyclic Electron Flow <ul><li>Occurs in the  thylakoid  membrane </li></ul><ul><li>Uses  Photosystem II  and  Photosyste...
Noncyclic Electron Flow H 2 O is split in PSII & ATP is made, while the energy carrier NADPH is made in PSI P700 Photosyst...
Noncyclic Electron Flow <ul><li>ADP +    ATP </li></ul><ul><li>NADP +  +  H       NADPH </li></ul><ul><li>Oxygen  comes...
 
NADP 2H+ ADP ATP PSII PSI X Y Solar energy Light Reaction NADPH 2 Solar energy H 2 O O 2 Solarenergy is converted to chemi...
2H+ ADP ATP PSII PSI X Y Light Reaction NADPH 2 H 2 O O 2 PHOTOLYSIS of WATER Exited electrons are released from  PSII Pic...
NADP 2H+ ADP ATP PSII PSI X Y LIGHT REACTION NADPH 2 H 2 O O 2 PHOTOLYSIS of WATER Exited electrons are released from PS I...
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Photosynthesis

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Transcript of "Photosynthesis"

  1. 1. Photosynthesis
  2. 2. <ul><li>LIFE ON EARTH ULTIMATELY DEPENDS ON ENERGY </li></ul>
  3. 3. So what is ENERGY? <ul><li>Some define it as the ability to </li></ul><ul><li>work. </li></ul><ul><li>In physics the capacity of the body or a system to do work. </li></ul>
  4. 4. Energy can be transformed from one form to another
  5. 5. SOURCES OF ENERGY <ul><li>COAL </li></ul><ul><li>OIL </li></ul>
  6. 6. THE SUN: MAIN SOURCE OF ENERGY FOR LIFE ON EARTH
  7. 7. What is photosynthesis? <ul><li>The process that plants use to make their own food </li></ul><ul><li>Plants’ leaves contain chlorophyll </li></ul><ul><li>Chlorophyll ( green color ) makes photosynthesis possible </li></ul>
  8. 8. <ul><li>THE GENERAL PROCESS </li></ul>
  9. 9. The chlorophyll absorbs the sunlight .
  10. 10. The sunlight is combined with water , Carbon Dioxide and nutrients from the soil . CO 2
  11. 11. The chlorophyll processes the ingredients and makes sugar (plant food) and oxygen. Sugar + Air O 2
  12. 12. THE FORMULA <ul><li>6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 </li></ul>glucose SUN
  13. 13. <ul><li>IN ECOLOGICAL PRINCIPLE….. </li></ul>
  14. 14. Plants and animals need each other to survive.
  15. 15. Animals including humans make the CO 2 (carbon dioxide) plants need. They (the plants) make the O 2 (oxygen) and food we need.
  16. 16. <ul><li>LIFE ON EARTH ULTIMATELY DEPENDS ON ENERGY </li></ul>
  17. 17. The chlorophyll absorbs the sunlight .
  18. 18. The chlorophyll processes the ingredients and makes sugar (plant food) and oxygen. Sugar + Air O 2
  19. 19. <ul><li>THE PHYSICAL AND CHEMICAL PROCESS </li></ul>
  20. 20. Two Parts of Photosynthesis <ul><li>Two reactions make up photosynthesis: </li></ul><ul><li>1. Light Reaction or Light Dependent Reaction - </li></ul><ul><li>Produces energy from solar power (photons) in the form of ATP and NADPH. </li></ul>SUN
  21. 21. Two Parts of Photosynthesis <ul><li>2. Calvin Cycle or Light Independent Reaction </li></ul><ul><li>Also called Carbon Fixation or C 3 Fixation </li></ul><ul><li>Uses energy ( ATP and NADPH ) from light reaction to make sugar (glucose). </li></ul>
  22. 22. Redox Reaction <ul><li>The transfer of one or more electrons from one reactant to another </li></ul><ul><li>Two types: </li></ul><ul><li>1. Oxidation is the loss of e - </li></ul><ul><li>2. Reduction is the gain of e - </li></ul>
  23. 23. Reduction Reaction <ul><li>The gain of electrons to a substance or the loss of oxygen. </li></ul>glucose 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Reduction
  24. 24. Oxidation Reaction <ul><li>The loss of electrons from a substance or the gain of oxygen. </li></ul>Carbon dioxide Water Oxygen glucose 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Oxidation
  25. 25. Question: <ul><li>Where does photosynthesis take place? </li></ul>
  26. 26. <ul><li>Mainly occurs in the leaves: </li></ul><ul><li>a. stoma - pores </li></ul><ul><li>b. mesophyll cells </li></ul>Stoma Mesophyll Cell Chloroplast
  27. 27. Stomata (stoma) <ul><li>Pores in a plant’s cuticle through which water vapor and gases (CO 2 & O 2 ) are exchanged between the plant and the atmosphere. </li></ul>Found on the underside of leaves Stoma Guard Cell Guard Cell Carbon Dioxide (CO 2 ) Oxygen (O 2 )
  28. 28. Mesophyll Cell of Leaf Photosynthesis occurs in these cells! Cell Wall Nucleus Chloroplast Central Vacuole
  29. 29. Chloroplast <ul><li>Organelle where photosynthesis takes place. </li></ul>Thylakoid stacks are connected together Granum Thylakoid Stroma Outer Membrane Inner Membrane
  30. 30. Thylakoid Grana make up the inner membrane Thylakoids contain chlorophylls Thylakoid Membrane Thylakoid Space Granum
  31. 31. <ul><li>The location and structure of chloroplasts overview </li></ul>LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast Mesophyll CHLOROPLAST Intermembrane space Outer membrane Inner membrane Thylakoid compartment Thylakoid Stroma Granum Stroma Grana
  32. 32. LIGHT REACTION glucose 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 SUN
  33. 33. The chlorophyll absorbs the sunlight .
  34. 34. PROPERTIES OF LIGHT <ul><li>Light has properties of both particles and wave </li></ul><ul><ul><li>Wave: is characterized by a wavelength </li></ul></ul><ul><ul><li>wavelength -the distance between wave crest </li></ul></ul><ul><ul><li>frequency- the number of wave crest </li></ul></ul><ul><ul><li>Particle: called as photon </li></ul></ul>
  35. 35. Absorption of Light by Chlorophyll wavelength Absorption Chlorophyll absorbs blue-violet & red light best violet blue green yellow orange red
  36. 36. <ul><li>Chlorophyll (in its lowest energy/ground = Chl) absorbs a photon ( hv) and makes a transition to a higher energy or excited, state (Chl*) </li></ul><ul><li>Chl + hv Chl* </li></ul>
  37. 37. Excited state e  Heat Light Photon Light (fluorescence) Chlorophyll molecule Ground state 2 (a) Absorption of a photon (b) fluorescence of isolated chlorophyll in solution Excitation of chlorophyll in a chloroplast e 
  38. 38. Wavelength of Light (nm) ABSOPRTION OF LIGHT EXCITES Chl INTO HIGHER ENERGY STATE WHEN PHOTONS HAVE SHORTER WAVELENGTH 400 500 600 700 Short wave Long wave (more energy) (less energy)
  39. 39. SPECIFIC SITE OF ABSORPTION IN CHLOROPLAST <ul><li>Light is absorbed in the integral membrane components of the thylakoid: </li></ul><ul><ul><li>Antenna complexes </li></ul></ul><ul><ul><ul><li>Chlorophylls, accessory pigments (carotenoids), and proteins </li></ul></ul></ul><ul><ul><li>Reaciton centers </li></ul></ul><ul><ul><ul><li>Photosystem I (PSI) and </li></ul></ul></ul><ul><ul><ul><li>Photosystem II (PSII) </li></ul></ul></ul>
  40. 40. <ul><li>Antenna complex </li></ul>SUN Reaction center Pigment molecules BASIC CONCEPT OF ENERGY TRANSFER DURING PHOTOSYNTHESIS <ul><li>Pigment collects light and transfer its energy to the reaction center </li></ul><ul><li>Reaction center is where chemical reactions store some energy by transferring electrons from the pigments to an electron acceptor molecule </li></ul>
  41. 41. POSSIBLE ROUTES FOR ELECTRON FLOW <ul><li>Cylclic electron flow </li></ul><ul><li>Non-cyclic electron flow </li></ul>
  42. 42. Cyclic Electron Flow <ul><li>Occurs in the thylakoid membrane. </li></ul><ul><li>Uses Photosystem I only </li></ul><ul><li>P700 reaction center- chlorophyll a </li></ul><ul><li>Uses Electron Transport Chain (ETC) </li></ul><ul><li>Generates ATP only </li></ul><ul><li>ADP + ATP </li></ul>P
  43. 43. Cyclic Electron Flow Pigments absorb light energy & excite e- of Chlorophyll a to produce ATP P700 Primary Electron Acceptor e - e - e - e - ATP produced by ETC Photosystem I Accessory Pigments SUN Photons
  44. 44. Noncyclic Electron Flow <ul><li>Occurs in the thylakoid membrane </li></ul><ul><li>Uses Photosystem II and Photosystem I </li></ul><ul><li>P680 reaction center (PSII) - chlorophyll a </li></ul><ul><li>P700 reaction center (PS I) - chlorophyll a </li></ul><ul><li>Uses Electron Transport Chain (ETC) </li></ul><ul><li>Generates O 2 , ATP and NADPH </li></ul>
  45. 45. Noncyclic Electron Flow H 2 O is split in PSII & ATP is made, while the energy carrier NADPH is made in PSI P700 Photosystem I P680 Photosystem II Primary Electron Acceptor Primary Electron Acceptor ETC Enzyme Reaction H 2 O 1/2O 2 + 2H + ATP NADPH Photon 2e - 2e - 2e - 2e - 2e - SUN Photon
  46. 46. Noncyclic Electron Flow <ul><li>ADP +  ATP </li></ul><ul><li>NADP + + H  NADPH </li></ul><ul><li>Oxygen comes from the splitting of H 2 O, not CO 2 </li></ul><ul><li> H 2 O  1/2 O 2 + 2H + </li></ul>P
  47. 48. NADP 2H+ ADP ATP PSII PSI X Y Solar energy Light Reaction NADPH 2 Solar energy H 2 O O 2 Solarenergy is converted to chemical energy ia ATP & NADPH 2. T hey are used in the Dark reaction a ADP
  48. 49. 2H+ ADP ATP PSII PSI X Y Light Reaction NADPH 2 H 2 O O 2 PHOTOLYSIS of WATER Exited electrons are released from PSII Picked up by low enrgy electron accepter Photophosphorylationh Electrons are activated by the light energy absorbed by PS I Exited electrons are released from PSI Picked up by low enrgy electron accepter Electrons are activated by PS 11 Electrons produced in the photolysis of water are gained by PS II Electrons are accepted by NADP to produced NADPH 2 Soloar Energy is absorbed by PS II 2H+ O 2 ADP Passed along a sequence of low energy electron carriers Soloar Energy is absorbed by PS I
  49. 50. NADP 2H+ ADP ATP PSII PSI X Y LIGHT REACTION NADPH 2 H 2 O O 2 PHOTOLYSIS of WATER Exited electrons are released from PS II picked up by a low energy electron accepter Passed along a series of electron accepters Electrons are activated by PS I Exited electrons are released Picked up by a low energy electron accepter Electrons are activated by PS II Electrons released from photolysis of water are accepted by PS II Electrons are accepeted to NADP + to form NADPH 2 Solar energy is absorbed by PS II O 2 Solar energy absorbed by PS I 1 2 3 4 5 5 6 8 7 9 9 10 11 12 PHOTOPHOSPHORYLATION
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