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Review Question Which mode of nutrition do the green plants carry out? A.Autotrophic nutrition B.Heterotrophic nutrition.

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Presentation on theme: "Review Question Which mode of nutrition do the green plants carry out? A.Autotrophic nutrition B.Heterotrophic nutrition."— Presentation transcript:

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3 Review Question Which mode of nutrition do the green plants carry out? A.Autotrophic nutrition B.Heterotrophic nutrition

4 Sorry! You’re wrong! Heterotrophic nutrition is the mode of nutrition in which organisms have to depend on other organisms or dead organic matters as their food sources. Green plants, however, can make organic food by themselves using simple inorganic substances. Back

5 Very Good! Autotrophic nutrition is the mode of nutrition in which organisms can make organic food by themselves using simple inorganic substances. The process by which the green plants obtain nutrients is called :- Photosynthesis

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7 Overview of nutrition in green plants carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids nutrients for plants can be used to produce all plant materials (e.g. enzymes, cell wall, cytoplasm, cell membrane, chlorophyll)

8 Nature of photosynthesis Anabolic process Takes place in chloroplast Necessary factors : Carbon dioxide Water Sunlight Chlorophyll

9 Light

10 Light Absorption Spectrum Why leave looked green?

11 Different pigments in absorption spectrum

12 How light energy used?

13 Light reaction Light energy is trapped by chlorophyll in chloroplast

14 Light reaction Light energy absorbed by chlorophyll splits water molecules into hydrogen and oxygen

15 Light reaction Oxygen is released as a gas through stoma to outside

16 Light reaction Hydrogen is fed into dark reaction

17 Dark reaction No light is required; can take place either in light or darkness Hydrogen produced in light reaction combines with CO 2 to form carbohydrates Water is formed as a by-product

18 Chlorophyll Structure

19 Light Reaction Photophosphorylation

20 Cyclic photophosphorylation

21 Dark Reaction M. Calvin

22 Calvin Cycle

23 CHLOROPLAST

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25 Fate of product of photosynthesis Kreb cycle

26 Factors affect rate of photosynthesis

27 Expt. Show effect of factors Distance Heat Conc. Of NaHCO 3

28 Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids

29 carbohydrates (e.g. glucose) Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids release energy by respiration

30 carbohydrates (e.g. glucose) Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids convert into starch for storage

31 Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids change into sucrose and is transported to other parts through phloem

32 Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts (e.g. NO 3 -, SO 4 2- ) water fatty acidsglycerol amino acids combine to form fats and oils to form cell membranes and as a food store

33 Fate of carbohydrate products in the plant carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts (e.g. NO 3 -, SO 4 2- ) waterfatty acidsglycerolamino acids join together to become protein molecules

34 Mineral requirements in plants In order to synthesize amino acids, nitrate ions must be taken into the plant from the soil through the root Other minerals are also necessary to maintain the life of the plant

35 Expt. Show effect of minerals Different Nutrient added

36 The importance of nitrogen For synthesis of proteins, chlorophyll, etc. Taken in the form of nitrate ions Deficiency symptoms: –Little growth (  no protein made) –Yellowing of leaves (  chlorophyll made)

37 The importance of magnesium Essential component of chlorophyll Deficiency symptoms: –Yellowing of leaves (  no chlorophyll made) –Poor growth (  no food manufactured because of lack of chlorophyll)

38 Use of fertilizers in agriculture Continuous harvesting crops removes the valuable mineral salts from soil  Fertilizers are added to replace such loss Two kinds of fertilizers: –Natural fertilizers –Chemical fertilizers

39 Natural fertilizers From manure Organic compounds in it are decomposed by bacteria in soil to form mineral salts

40 Chemical fertilizers Mainly nitrogenous and phosphorous compounds manufactured artificially

41 Comparison between natural and chemical fertilizers Natural fertilizersChemical fertilizers Very cheapMore expensive Contain humus which can improve soil texture No humus so cannot improve soil texture Less soluble in water so less likely to be washed away Very soluble in water so more likely to be washed away

42 Comparison between natural and chemical fertilizers Natural fertilizersChemical fertilizers Less soluble in water so more difficult to be absorbed Very soluble in water so easier to be absorbed More readily to be used by the plants Time is needed for the decomposition to complete before nutrient is available to plants

43 Importance of photosynthesis It is the only method to convert energy in sunlight into chemical energy –Animals have to depend on plants for food supply –Plants: producers; animals : consumers To maintain a constant oxygen level in the atmosphere

44 Experiments to test for necessary factors of photosynthesis Experimental set-up: To remove the factor under study and to see if photosynthesis still takes place Control set-up: Identical to experimental set-up except that the missing factor is present

45 A set-up to study whether light is necessary for photosynthesis

46 Which is the control, the exposed region A or the shaded region B?

47 To show that photosynthesis cannot take place in the absence of light What is the purpose of setting up region A? As a control Too simple and not explicit!

48 Destarching Reason: –To avoid any existing starch in the leaves interfering with the result, and to show that any starch found after the experiment was produced during the period of investigation Method: –By placing the plant in dark for at least 24 hours

49 Parts of plant where photosynthesis takes place Places where chloroplasts are found Mainly in the leaf because –it contains a lot of chloroplasts –it is well adapted for performing photosynthesis

50 Cross-section of a dicot leaf upper epidermis protect internal tissues from mechanical damage and bacterial and fungal invasion

51 Cross-section of a dicot leaf Cuticle a waxy layer prevent water loss from the leaf surface

52 Cross-section of a dicot leaf mesophyll

53 Cross-section of a dicot leaf palisade mesophyll columnar cells closely packed together absorb light more efficiently contains many chloroplasts

54 Cross-section of a dicot leaf spongy mesophyll irregular cells loosely packed together to leave numerous large air spaces allow rapid diffusion of gases throughout the leaf less chloroplasts for photosynthesis

55 Cross-section of a dicot leaf lower epidermis same as upper epidermis except the cuticle is thinner

56 Cross-section of a dicot leaf stoma opening which allows gases to pass through it to go into or out of the leaf

57 Cross-section of a dicot leaf guard cells control the size of stoma

58 Cross-section of a dicot leaf vascular bundle (vein)

59 Cross-section of a dicot leaf xylem to transport water and mineral salts towards the leaf

60 Cross-section of a dicot leaf phloem to transport organic substances away from the leaf

61 Adaptation of leaf to photosynthesis Upper epidermis and cuticle is transparent Allows most light to pass to photosynthetic mesophyll tissues

62 Adaptation of leaf to photosynthesis Palisade mesophyll cells are closely packed and contain many chloroplasts To carry out photosynthesis more efficiently

63 Adaptation of leaf to photosynthesis Spongy mesophyll cells are loosely packed with numerous large air spaces To allow rapid diffusion of gases throughout the leaf

64 Adaptation of leaf to photosynthesis Numerous stomata on lower epidermis To allow rapid gaseous exchange with the atmosphere

65 Adaptation of leaf to photosynthesis Extensive vein system Allow sufficient water to reach the cells in the leaf To carry food away from them to other parts of the plant

66 CHEMOSYNTHSIS Iron bacteria Colorless sulphur bacteria Nitrifying bacteria

67 Iron bacteria

68 Nitrifying bacteria

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