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Photosynthesis 光合作用

Photosynthesis 光合作用. 香港道教聯合會青松中學 吳友強. Chloroplast under electron microscope. 電子顯微鏡下的葉綠體. Quick Revision : Where does photosynthesis occur ？. Leaf 葉片. X-section 橫切面 : Palisade mesophyll 柵狀葉肉. Chloroplast 葉綠體. Warm-up Questions.

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Photosynthesis 光合作用

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  1. Photosynthesis光合作用 香港道教聯合會青松中學 吳友強

  2. Chloroplast under electron microscope 電子顯微鏡下的葉綠體 Quick Revision : Where does photosynthesis occur？ Leaf 葉片 X-section 橫切面 : Palisade mesophyll 柵狀葉肉 Chloroplast葉綠體

  3. Warm-up Questions The following microphotograph is a transverse section of a A. stem. B. leaf. C. root.

  4. Sorry, you’ve got the wrong answer!!! Can you find cortex (皮層), which is very obvious in a cross-section of a stem ? Try again...

  5. Sorry, you’ve got the wrong answer!!! Are the vascular bundles(維管束)concentrated in the centre of the section ? Try again...

  6. Congratulations!!! You’ve got the correct answer!!! Go to next question...

  7. Warm-up Questions Here is a transverse section of a leaf. It is a leaf of A. monocotyledonousxerophyte B. dicotyledonoushydrophyte C. dicotyledonousmesophyte

  8. Sorry, you’ve got the wrong answer!!! Xerophyte is a kind of plants adapted in desert habitat. Try again...

  9. Sorry, you’ve got the wrong answer!!! Hydrophyte is a kind of plants adapted in aquatic habitat. Try again...

  10. Congratulations!!! You’ve got the correct answer!!! Bonus …….

  11. ??? ??? ??? Bonus : Give two reasons to support your answer. Hints -----

  12. Definition of Photosynthesis Photosynthesis is a process by which green plants use sunlight trapped by chlorophyll to produce organic compounds (carbodyrate) from carbon dioxide and water, oxygen is released as by-product.

  13. Summary of Photosynthesis Sunlight 陽光 Carbon dioxide 二氧化碳 Water 水 Chlorophyll 葉綠素 Oxygen 氧 Glucose 葡萄糖

  14. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll Experiments : light 1.To show that starch is produced during Photosynthesis.

  15. Four steps : 1.Boil the leaf in water, why ? 2.Boil the leaf in alcohol, why ? 3.Wash the leaf in warm water, why ? 4.Add iodine solution to the leaf, what is the expected result ?

  16. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll Experiments : light Aim : To show that light is necessary for Photosynthesis. Control : Do we need a Control for this experiment ?

  17. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll Experiments : light Aim : To show that chlorophyll is necessary for photosynthesis. Control : Do we need a Control for this experiment ? Any Assumption ?

  18. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll Experiments : light Aim : To show that carbon dioxide is necessary for photosynthesis. Any Criticism on the set-up ? (Think about Variables.)

  19. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll light Is it better ?

  20. 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll Experiments : light Aim : To show that oxygen is produced during photosynthesis.

  21. Logics In an experiment, think about : Aim and objective Control experiment Dependent variables Independent variables Assumptions Limitations

  22. Limitations of the summary equation :　　 light 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll 1.Photosynthesis is a two phase process, which cannot be shown in the equation. 2.Source of oxygen cannot be shown. 3.Glucose is not the first product of photosynthesis.

  23. Photosynthesis involves two stages : • Light reaction • light is necessary • light split water into hydrogen and oxygen • Dark reaction • light is not necessary • hydrogen is used to reduce carbon dioxide to carbodyrate

  24. Light reaction Light 陽光 Water 水 Oxygen 氧 Hydrogen氫 （原子） Chlorophyll 葉綠素 Released from the plant Dark reaction

  25. Dark reaction Hydrogen氫 （原子） Carbohydrate 碳水化合物 Carbon dioxide 二氧化碳

  26. This powerpoint was kindly donated to www.worldofteaching.com http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.

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