2015/4/30 Leaf 葉片 X-section 橫切面 : Palisade mesophyll 柵狀葉肉 Chloroplast 葉綠體 Quick Revision : Where does photosynthesis occur ？ 電子顯微鏡下的葉綠體 Chloroplast under electron microscope
2015/4/30 Warm-up Questions The following microphotograph is a transverse section of a A. stem. B. leaf. C. root.
2015/4/30 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...
2015/4/30 Sorry, you’ve got the wrong answer!!! Are the vascular bundles( 維管束 ) concentrated in the centre of the section ? Try again...
2015/4/30 Congratulations!!! You’ve got the correct answer!!! Go to next question...
2015/4/30 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
2015/4/30 Sorry, you’ve got the wrong answer!!! Xerophyte is a kind of plants adapted in desert habitat. Try again...
2015/4/30 Sorry, you’ve got the wrong answer!!! Hydrophyte is a kind of plants adapted in aquatic habitat. Try again...
2015/4/30 Congratulations!!! You’ve got the correct answer!!! Bonus …….
2015/4/30 Bonus : Give two reasons to support your answer. Hints ----- ??? ??? ???
2015/4/30 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.
2015/4/30 Summary of Photosynthesis Carbon dioxide 二氧化碳 Water 水 Oxygen 氧 Glucose 葡萄糖 Chlorophyll 葉綠素 Sunlight 陽光
2015/4/30 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
2015/4/30 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 ?
2015/4/30 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
2015/4/30 Experiments : Aim : To show that chlorophyll is necessary for photosynthesis. light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll Control : Do we need a Control for this experiment ? Any Assumption ?
2015/4/30 Experiments : Aim : To show that carbon dioxide is necessary for photosynthesis. light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll Any Criticism on the set-up ? (Think about Variables.)
2015/4/30 Is it better ? light 6CO 2 ＋ 6H 2 O C 6 H 12 O 6 + 6O 2 chlorophyll
2015/4/30 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
2015/4/30 Logics In an experiment, think about : Aim and objective Control experiment Dependent variables Independent variables Assumptions Limitations
2015/4/30 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
2015/4/30 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
2015/4/30 Water 水 Light 陽光 Chlorophyll 葉綠素 Oxygen 氧 Hydrogen 氫 （原子） Released from the plant Dark reaction Light reaction
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