All you ever wanted  to know about photosynthesis  but were afraid  to ask!
Leaf Structure <ul><li>Most photosynthesis occurs in the  palisade  layer. </li></ul><ul><li>Gas exchange of CO 2  and O 2...
Chloroplast Structure <ul><li>Inner membrane called the  thylakoid  membrane. </li></ul><ul><li>Thickened regions called  ...
Overview of photosynthesis and respiration PHOTOSYNTHESIS CELL ACTIVITIES RESPIRATION SUN RADIANT ENERGY GLUCOSE ATP(ENERGY)
EQUATION   FOR   PHOTOSYNTHESIS 6CO 2  + 6H 2 O  + ENERGY C 6 H 12 O 6  + 6O 2   CARBON DIOXIDE WATER GLUCOSE OXYGEN
EQUATION FOR   RESPIRATION C 6 H 12 O 6  + GLUCOSE 6O 2 OXYGEN 6CO 2  + CARBON DIOXIDE 6H 2 O  + ENERGY WATER ATP
Photosynthesis in Overview <ul><li>Process by which plants and other autotrophs store the energy of sunlight into sugars. ...
Photosynthesis: The Chemical Process <ul><li>Occurs in two main phases. </li></ul><ul><ul><li>Light reactions </li></ul></...
Light Reactions <ul><li>Light-dependent reactions occur on the thylakoid membranes. </li></ul><ul><ul><li>Light and water ...
Dark Reactions <ul><li>Dark reactions (light-independent) occur in the stroma. </li></ul><ul><ul><li>Carbon dioxide is “fi...
The photosynthetic reaction <ul><ul><li>Water +  ADP   – sunlight ->  oxygen +  hydrogen ions  +  ATP </li></ul></ul><ul><...
Plant Structures
General leaf adaptations <ul><li>Flat shape  . </li></ul><ul><li>Many stomatal pores </li></ul><ul><li>Very thin with inte...
General stem adaptations <ul><li>Xylem vessels running entire length </li></ul><ul><li>Rigid structure of xylem </li></ul>...
General adaptations of roots <ul><li>Broad and deep spread of roots  . </li></ul><ul><li>Root hairs </li></ul><ul><li>Taps...
 
 
Plant  Transport  Systems
 
 
Xylem <ul><li>Water and mineral are transported from the roots to the photosynthetic areas of the plant. </li></ul><ul><li...
 
 
Transpiration moves water and minerals up the stem of the plant
Movement of water through the xylem <ul><li>Water transpires from stomatal pores </li></ul><ul><li>… which is replaced by ...
Phloem <ul><li>Glucose is produced through the process of photosynthesis in the leaves and is then packaged in to sucrose ...
 
 
<ul><li>Transport of sugars is performed via active transport & osmosis. </li></ul><ul><li>ATP is provided by the companio...
 
Ringbarking
I would never do that! Gaseous echange in plants
For what purposes is gaseous exchange required? <ul><li>Photosynthesis </li></ul><ul><ul><li>Intake of carbon dioxide </li...
Mechanisms for gaseous exchange <ul><li># 1 Stomata </li></ul><ul><li>Stomata comprise of an opening, the stoma and two gu...
 
Structure of a guard cell Cellulose fibrils Thick cell wall Thin cell wall When the guard cell swells with water, it bows ...
Effect of Chloroplasts on Stomata function K + K + K + ATP H 2 O
Opening of stomata <ul><li>Sun shines on plant </li></ul><ul><li>Chloroplasts carry out photosynthesis 1 (light dependant)...
Mechanisms for gaseous exchange <ul><li># 2 Lenticels </li></ul><ul><li>The woody part of plants is still growing, and the...
Lenticels Lenticel (dead) cork cambium (living)  parenchyma  cells
Altered photosynthetic cycle in desert plants <ul><li>Desert plants would lose too much water if they opened their stomata...
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09 Photosynthesis & plant structures

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09 Photosynthesis & plant structures

  1. 1. All you ever wanted to know about photosynthesis but were afraid to ask!
  2. 2. Leaf Structure <ul><li>Most photosynthesis occurs in the palisade layer. </li></ul><ul><li>Gas exchange of CO 2 and O 2 occurs at openings called stomata surrounded by guard cells on the lower leaf surface. </li></ul>Palisade Spongy
  3. 3. Chloroplast Structure <ul><li>Inner membrane called the thylakoid membrane. </li></ul><ul><li>Thickened regions called thylakoids . A stack of thylakoids is called a granum . (Plural – grana) </li></ul><ul><li>Stroma is a liquid surrounding the thylakoids. </li></ul>
  4. 4. Overview of photosynthesis and respiration PHOTOSYNTHESIS CELL ACTIVITIES RESPIRATION SUN RADIANT ENERGY GLUCOSE ATP(ENERGY)
  5. 5. EQUATION FOR PHOTOSYNTHESIS 6CO 2 + 6H 2 O + ENERGY C 6 H 12 O 6 + 6O 2 CARBON DIOXIDE WATER GLUCOSE OXYGEN
  6. 6. EQUATION FOR RESPIRATION C 6 H 12 O 6 + GLUCOSE 6O 2 OXYGEN 6CO 2 + CARBON DIOXIDE 6H 2 O + ENERGY WATER ATP
  7. 7. Photosynthesis in Overview <ul><li>Process by which plants and other autotrophs store the energy of sunlight into sugars. </li></ul><ul><li>Requires sunlight, water, and carbon dioxide. </li></ul><ul><li>Overall equation: </li></ul><ul><li>6 CO 2 + 6 H 2 0  C 6 H 12 O 6 + 6 O 2 </li></ul><ul><li>Occurs in the leaves of plants in organelles called chloroplasts. </li></ul>
  8. 8. Photosynthesis: The Chemical Process <ul><li>Occurs in two main phases. </li></ul><ul><ul><li>Light reactions </li></ul></ul><ul><ul><li>Dark reactions </li></ul></ul><ul><li>Light reactions are the “photo” part of photosynthesis. Light is absorbed by pigments. </li></ul><ul><li>Dark reactions are the “synthesis” part of photosynthesis. Trapped energy from the sun is converted to the chemical energy of sugars. </li></ul>
  9. 9. Light Reactions <ul><li>Light-dependent reactions occur on the thylakoid membranes. </li></ul><ul><ul><li>Light and water are required for this process. </li></ul></ul><ul><ul><li>Energy storage molecules are formed. (ATP and NADPH) </li></ul></ul><ul><ul><li>Oxygen gas is made as a waste product. </li></ul></ul>
  10. 10. Dark Reactions <ul><li>Dark reactions (light-independent) occur in the stroma. </li></ul><ul><ul><li>Carbon dioxide is “fixed” into the sugar glucose. </li></ul></ul><ul><ul><li>ATP and NADPH molecules created during the light reactions power the production of this glucose. </li></ul></ul>
  11. 11. The photosynthetic reaction <ul><ul><li>Water + ADP – sunlight -> oxygen + hydrogen ions + ATP </li></ul></ul><ul><ul><li>Carbon dioxide + hydrogen ions + ATP -> glucose + ADP </li></ul></ul>H 2 O + ADP + CO 2 + H + + ATP --sunlight-> O 2 + H + + ATP + C 6 H 12 O 6 + ADP 6H 2 O + 6CO 2 --sunlight-> 6O 2 + C 6 H 12 O 6
  12. 12. Plant Structures
  13. 13. General leaf adaptations <ul><li>Flat shape . </li></ul><ul><li>Many stomatal pores </li></ul><ul><li>Very thin with internal air chambers </li></ul><ul><li>Extensive network of vascular tissue </li></ul><ul><ul><li>Xylem </li></ul></ul><ul><ul><li>Phloem </li></ul></ul><ul><li>Large photosynthetic surface </li></ul><ul><li>Gaseous exchange </li></ul><ul><li>Easy diffusion of CO 2 to photosynthetic cells </li></ul><ul><li>Delivery of essential nutrients </li></ul><ul><ul><li>Water & minerals </li></ul></ul><ul><ul><li>Sucrose & hormones </li></ul></ul>
  14. 14. General stem adaptations <ul><li>Xylem vessels running entire length </li></ul><ul><li>Rigid structure of xylem </li></ul><ul><li>Phloem vessels running entire length </li></ul><ul><li>Branching of stem . . </li></ul><ul><li>Transport water and minerals from roots </li></ul><ul><li>Helps plant to remain upright </li></ul><ul><li>Transports sucrose from leaves </li></ul><ul><li>Provides broader, multileveled photosynthetic area </li></ul>
  15. 15. General adaptations of roots <ul><li>Broad and deep spread of roots . </li></ul><ul><li>Root hairs </li></ul><ul><li>Taps a large area of soil for water and nutrients </li></ul><ul><li>Provide larger surface area for absorption of water and minerals </li></ul>
  16. 18. Plant Transport Systems
  17. 21. Xylem <ul><li>Water and mineral are transported from the roots to the photosynthetic areas of the plant. </li></ul><ul><li>Composed of dead, hollow cells </li></ul><ul><li>Provides extra internal support for plant </li></ul><ul><li>Water moves up the plant through the process of a transpiration vacuum. </li></ul>
  18. 24. Transpiration moves water and minerals up the stem of the plant
  19. 25. Movement of water through the xylem <ul><li>Water transpires from stomatal pores </li></ul><ul><li>… which is replaced by water from the air spaces in the mesophyll </li></ul><ul><li>… which is replaced by H 2 O in leaf cells </li></ul><ul><li>… which is replaced by H 2 O in leaf xylem </li></ul><ul><li>… which is replaced by H 2 O in stem xylem </li></ul><ul><li>… which is replaced by H 2 O in root xylem </li></ul><ul><li>… which is replaced by drawing H 2 O from soil </li></ul>Movement of water through the xylem
  20. 26. Phloem <ul><li>Glucose is produced through the process of photosynthesis in the leaves and is then packaged in to sucrose </li></ul><ul><li>Transported through living sieve cells of the phloem, along with hormones to the non-photosynthetic parts of the plant known as ‘sinks’. </li></ul><ul><li>This movement is known as ‘translocation’ </li></ul><ul><li>Sugars are either stored as starch or broken down in to monosaccarides and metabolised for growth </li></ul>
  21. 29. <ul><li>Transport of sugars is performed via active transport & osmosis. </li></ul><ul><li>ATP is provided by the companion cells </li></ul><ul><li>High sugar content in sap in leaf phloem causes intake of water via osmosis </li></ul><ul><li>As sugar is transported out of phloem at sinks, water returns to xylem via osmosis. </li></ul><ul><li>Therefore there is a region of high pressure at the source and low pressure at the sinks, facilitating movement of sap </li></ul>Movement of sugars through the phloem
  22. 31. Ringbarking
  23. 32. I would never do that! Gaseous echange in plants
  24. 33. For what purposes is gaseous exchange required? <ul><li>Photosynthesis </li></ul><ul><ul><li>Intake of carbon dioxide </li></ul></ul><ul><ul><li>Disposal of excess oxygen </li></ul></ul><ul><li>Respiration </li></ul><ul><ul><li>Intake of oxygen </li></ul></ul><ul><ul><li>Disposal of excess carbon dioxide </li></ul></ul>
  25. 34. Mechanisms for gaseous exchange <ul><li># 1 Stomata </li></ul><ul><li>Stomata comprise of an opening, the stoma and two guard cells either side. </li></ul><ul><li>When the guard cells are turgid (full of water) the stomata is open </li></ul><ul><li>When the guard cells are flaccid (empty) the stomata is closed </li></ul>
  26. 36. Structure of a guard cell Cellulose fibrils Thick cell wall Thin cell wall When the guard cell swells with water, it bows in to the shape of a jelly bean.
  27. 37. Effect of Chloroplasts on Stomata function K + K + K + ATP H 2 O
  28. 38. Opening of stomata <ul><li>Sun shines on plant </li></ul><ul><li>Chloroplasts carry out photosynthesis 1 (light dependant) </li></ul><ul><li>ATP from photosynth powers NA/K pump </li></ul><ul><li>K + ions pumped in to guard cells, thus creating a concentration gradient </li></ul><ul><li>Water enters cell via osmosis </li></ul><ul><li>Guard cells swell, stomata opens </li></ul>
  29. 39. Mechanisms for gaseous exchange <ul><li># 2 Lenticels </li></ul><ul><li>The woody part of plants is still growing, and therefore performing cellular respiration. (O 2 in, CO 2 out) </li></ul><ul><li>Lenticels are a protrusion of living cells in to the dead cambium layer </li></ul>
  30. 40. Lenticels Lenticel (dead) cork cambium (living) parenchyma cells
  31. 41. Altered photosynthetic cycle in desert plants <ul><li>Desert plants would lose too much water if they opened their stomata during the day. </li></ul><ul><li>Instead they only perform photosynthesis 1 during the day. </li></ul><ul><li>Then at night they release the stored waste O 2 and take in CO 2 to complete the photosynthetic process. </li></ul>
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