7. 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
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...
11. Bonus : Give two reasons to support your answer. ??? ??? ???
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 Carbon dioxide 二氧化碳 Water 水 Oxygen 氧 Glucose 葡萄糖 Chlorophyll 葉綠素 Sunlight 陽光
14. Experiments : 1.To show that starch is produced during Photosynthesis. light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
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. Experiments : Aim : To show that light is necessary for Photosynthesis. Control : Do we need a Control for this experiment ? light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
17. Experiments : Aim : To show that chlorophyll is necessary for photosynthesis. light Control : Do we need a Control for this experiment ? Any Assumption ? 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
18. Experiments : Aim : To show that carbon dioxide is necessary for photosynthesis. light Any Criticism on the set-up ? (Think about Variables.) 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
19. Is it better ? light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
20. Experiments : Aim : To show that oxygen is produced during photosynthesis. light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
21. Logics In an experiment, think about : Aim and objective Control experiment Dependent variables Independent variables Assumptions Limitations
22. Limitations of the summary equation : 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. 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 light chlorophyll
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24. Water 水 Light 陽光 Chlorophyll 葉綠素 Oxygen 氧 Hydrogen 氫 （原子） Released from the plant Dark reaction Light reaction
