Photosynthesis 2013 new


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Photosynthesis 2013 new

  1. 1. PHOTOSYNTHESISPHOTOSYNTHESISPHOTOSYNTHESISPHOTOSYNTHESIS state what photosynthesis isstate what photosynthesis is state the factors required forstate the factors required for photosynthesisphotosynthesis state the products ofstate the products of photosynthesisphotosynthesis
  2. 2. Check it! Plants in Action What is the process that uses the sun’s energy to make simple sugars?
  3. 3. Photosynthesis  is the process in which green plants use light to produce food  green plants manufacture glucose from water and carbon dioxide in the presence of sunlight trapped in their chlorophyll.  oxygen is released in the process  glucose is stored as starch in the plant + +Carbon dioxide Water Glucose Oxygen Light energy from the sun Trapped by chlorophyll
  4. 4.  CARBON DIOXIDE from the air  WATER absorb by the roots from the soil  CHLOROPHYLL a green pigment in the leaf of green plant absorbs the sun’s energy convert sun’s energy to glucose  GLUCOSE stored as starch in other parts of plant  OXYGEN release to the air + +
  5. 5. PlantsLeaves are green because they contain the pigment: chlorophyllchlorophyll Leaves have aLeaves have a large surface arealarge surface area to absorb as muchto absorb as much lightlight as possibleas possible "Thanks for the Glucose!""Thanks for the Glucose!"
  6. 6. Stoma This opening how plants exchange gases! Check it! Can you name the two important gases that go in and out of the leaves? Why are theWhy are the stomatastomata located on thelocated on the underside ofunderside of leaves?leaves?
  7. 7. REQUIREMENTS OF PHOTOSYNTHESIS chlorophylllight carbon dioxide water
  8. 8. To know whether photosynthesis is take place in a plant : • We can test for the presence of starch in the leaves Step Purpose Boiling the leaf in the water To break the cell wall Heating the leaf in alcohol To remove the chlorophyll in the cells Dipping the leaf in hot water To soften the leaf Adding iodine solution onto the leaf To test the presence of starch in the leaf
  9. 9. Alcohol was heated in a beaker of hot water Method of heating is WATER BATH Why should the alcohol be heated in this manner? Alcohol is flammable, so it will catch fire when heated directlly
  10. 10. If starch is present in a leaf, the leaf turns blue black/dark blue when tested by iodine solution Lets see the video
  11. 11. Determining the requirements of photosynthesis • To investigate whether carbon dioxide is required for photosynthesis 1. A potted plant was kept in the dark for two days 2. A potted plant was exposed to sunlight for two hours 3. Leaves X and Y were tested for the presence of starch  function potassium hydroxide pellets to absorb carbon dioxide in conical flask X
  12. 12. Determining the requirements of photosynthesis • To investigate whether carbon dioxide is required for photosynthesis Leaf Presence of carbon dioxide in flask Observation Inference X Absent The leaf turn brown Starch is not present, photosynthesis does not take place Y Present The leaf turned blue black Starch is present, photosynthesis