1. *
07/16/96
Photosynthesis 光合作用
香港道教聯合會青松中學
吳友強
2018/12/8 *

2. Where does photosynthesis occur？*
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Quick Revision :
Where does photosynthesis occur？
Leaf 葉片
X-section
橫切面 :
Palisade
mesophyll
柵狀葉肉
電子顯微鏡下的葉綠體
Chloroplast under electron microscope
Chloroplast葉綠體
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3. *
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Warm-up Questions
The following microphotograph is a transverse section of a
A. stem.
B. leaf.
C. root.
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4. Sorry, you’ve got the wrong answer!!!*
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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...
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5. Sorry, you’ve got the wrong answer!!!*
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Sorry, you’ve got the wrong answer!!!
Are the vascular bundles(維管束) concentrated in the centre
of the section ?
Try again...
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6. Congratulations!!! You’ve got the correct answer!!! Go to next*
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Congratulations!!!
You’ve got the
correct answer!!!
Go to next
question...
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7. *
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Warm-up Questions
Here is a transverse section of a leaf. It is a leaf of
A. monocotyledonous xerophyte
B. dicotyledonous hydrophyte
C. dicotyledonous mesophyte
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8. Sorry, you’ve got the wrong answer!!!*
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Sorry, you’ve got the wrong answer!!!
Xerophyte is a kind of plants adapted in desert habitat.
Try again...
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9. Sorry, you’ve got the wrong answer!!!*
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Sorry, you’ve got the wrong answer!!!
Hydrophyte is a kind of plants adapted in aquatic habitat.
Try again...
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10. Congratulations!!! You’ve got the correct answer!!! Bonus …….*
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Congratulations!!!
You’ve got the
correct answer!!!
Bonus …….
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11. Give two reasons to support your answer. Hints -----*
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Bonus :
Give two reasons to support your answer.
Hints -----
???
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12. Definition of Photosynthesis*
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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.
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13. Summary of Photosynthesis*
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Summary of Photosynthesis
Sunlight 陽光
Carbon dioxide
二氧化碳
Water 水
Chlorophyll
葉綠素
Oxygen 氧
Glucose
葡萄糖
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14. Experiments : 1.To show that starch is produced during Photosynthesis.*
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Experiments :
light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
1.To show that starch is produced during Photosynthesis.
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15. Four steps : 1.Boil the leaf in water, why ?*
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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 ?
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16. Experiments : Aim : Control : light 6CO2 ＋ 6H2O C6H12O6 + 6O2*
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Experiments :
light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
Aim :
To show that light is necessary for Photosynthesis.
Control :
Do we need a Control for this experiment ?
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17. Experiments : Aim : Control : Any Assumption ? light*
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Experiments :
light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
Aim :
To show that chlorophyll is necessary for photosynthesis.
Control :
Do we need a Control for this experiment ?
Any Assumption ?
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18. Experiments : Aim : Any Criticism on the set-up ?*
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Experiments :
light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
Aim :
To show that carbon dioxide is necessary for photosynthesis.
Any Criticism on the set-up ?
(Think about Variables.)
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19. Is it better ? light 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll 2018/12/8 *
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light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
Is it better ?
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20. Experiments : Aim : light 6CO2 ＋ 6H2O C6H12O6 + 6O2 chlorophyll*
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Experiments :
light
6CO2 ＋ 6H2O C6H12O6 + 6O2
chlorophyll
Aim :
To show that oxygen is produced during
photosynthesis.
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21. Logics In an experiment, think about : Aim and objective*
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Logics
In an experiment, think about :
Aim and objective
Control experiment
Dependent variables
Independent variables
Assumptions
Limitations
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22. Limitations of the summary equation : *
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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.
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23. Photosynthesis involves two stages :*
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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
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24. Light reaction Light 陽光 Water 水 Oxygen 氧 Hydrogen氫 （原子） Chlorophyll*
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Light reaction
Light 陽光
Water 水
Oxygen 氧
Hydrogen氫
（原子）
Chlorophyll
葉綠素
Released from
the plant
Dark reaction
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25. Dark reaction Hydrogen氫 （原子） Carbohydrate 碳水化合物 Carbon dioxide 二氧化碳*
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Dark reaction
Hydrogen氫
（原子）
Carbohydrate
碳水化合物
Carbon dioxide
二氧化碳
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26. This powerpoint was kindly donated to www.worldofteaching.com*
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This powerpoint was kindly donated to
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2018/12/8 *