Fungi kingdom


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Fungi kingdom

  1. 1. Monera Protist Plant AnimalFungi Fungi form a Kingdom on their own Fungi are: eukaryotic
  2. 2. Fungi range in size: unicellular yeasts large puffball 20-60 cm
  3. 3. General characteristics 1. Fungi have no chlorophyll  so cannot make their own food by photosynthesis How do fungi feed? 1. As parasites 2. As saprophytes
  4. 4. Parasites: (feed on a living host, causing it harm) Saprophytes: (feed on dead and decaying matter) Parasitic fungi on (i) nails and (ii) trees. (i) (ii)
  5. 5. 2. Fungi do not produce flowers. Reproduce by spores. 3. Fungi are mainly found in damp and shady places.
  6. 6. Question: SEP, 2011 Give a biological explanation for each of the following statements. Fungi are rarely found in brightly lit environments. (3) Do not photosynthesise. Lack a waxy cuticle – avoid drying up by avoiding such environments.
  7. 7. 4. The basic unit of a fungus is a hypha and not a cell. A. nucleus B. cell wall C. cytoplasm D. vacuole A hypha (plural = hyphae) is a thread-like structure having a cell wall made of chitin. Part of a hypha
  8. 8. Fungi store food as: glycogen or oil, but not starch Pin mould
  9. 9. A network of hyphae: a mycelium hyphae are either white or grey A hypha grows out of a germinating spore Mycelium
  10. 10. Two types of hyphae: feeding hyphae: are horizontal reproductive hyphae: are erect
  11. 11. Mucor belongs to the group of fungi called moulds – it is a pin mould lives on damp, organic (has carbon) matter such as:  bread  leather  fruit  leaf litter  horse dung
  12. 12. Structure of Mucor Spores in sporangium Erect reproductive hypha Sporangium (spore case) Feeding hypha
  13. 13. Asexual reproduction in Mucor: by producing spores
  14. 14. Spores are: i) small & light: to be carried easily by the wind or insects ii)numerous: to increase chances of survival
  15. 15. Nutrition in Mucor 3. Nutrients are absorbed from all over the hyphae. 1. Extracellular enzymes from growing tips. 2. Digestion takes place outside the body.
  17. 17. Fungi are useful: 1. Decay dead material and are important to recycle nutrients in the soil 2. Decompose sewage 3. Are used to make the antibiotic penicillin 4. Are eaten e.g. mushrooms 5. Yeast is useful to make bread, wine and beer
  18. 18. Fungi are harmful: 1. Parasitic fungi causes diseases in animals and plants 2. Spoil food, clothes, leather and walls Athlete’s foot in humans Rusts in wheat
  19. 19. Let us study YEAST: 1. Structure 2. Economic importance
  20. 20. A single yeast cell cell wall nucleus cytoplasm vacuole Yeast is a unicellular fungus
  21. 21. Yeast reproduces asexually by:
  22. 22. Yeast carries out: glucose ethanol + carbon + energy C6H12O6 2C2H5OH + 2CO2 + 210 kJ carbon dioxide
  23. 23. Dough making Wine making Beer making
  24. 24. 1. Dough making flour, yeast, sugar & water are mixed to make a dough Water must be warm and NOT boiling. WHY?
  25. 25. The living yeast cells multiply and ferment the sugar to give off carbon dioxide gas After 1 hour in a warm place the dough has risen.A close-up of the dough.
  26. 26. What happens to the alcohol during baking? It evaporates on baking. SEP 2013 Explain why it is important to produce a very sticky dough after mixing the ingredients together. (2) Carbon dioxide remains inside the dough. The gas makes the dough expand.
  27. 27. The ‘holes’ in the bread are made by the carbon dioxide bubbles. This gives the bread a ‘light’ texture SEP 2013 What happens to the yeast when the dough is baked in the oven? Why? (2) Dies. The heat kills it.
  28. 28. Question: SEP, 2007 Give biological reasons for the following statement: Yeast is added to flour for the pizza dough to rise. (2) Yeast releases carbon dioxide by fermentation. As carbon dioxide escapes, it makes the dough rise.
  29. 29. Barley seeds are soaked in water so that enzymes are made Enzymes convert the stored starch into sugar
  30. 30. the seeds are crushed with water the resulting liquid is boiled with hops to give it a flavour
  31. 31. Yeast is then added to ferment the sugar
  32. 32. The solution is placed in a fermenter or vat
  33. 33. Question The main stages in the brewing of beer are given in the diagram below. Stage B Barley or other cereal grains germinatedStage A Stage C Stage D Stage E Germinated grains crushed in water Yeast added to solution (from Stage B) and mixture placed in closed vats fitted with one-way exit valve Yeast dies and falls to bottom Liquid bottled a) Name the principal carbohydrate stored in cereal grains (Stage A). Starch
  34. 34. b) What conditions are needed for the barley to germinate? Water, a correct temperature, oxygen c) Describe the action of the yeast on the solution in Stage C. (3) Yeast ferments the sugar into carbon dioxide, ethanol and energy. The process is anaerobic.
  35. 35. d) Why were the vats closed and fitted with one-way exit valves in Stage C? (3) To prevent microbes & oxygen from entering. To allow carbon dioxide to escape or else the fermenter bursts. e) What was the most likely cause of death of the yeast in Stage D? (Assume that the supply of food was adequate.) (1) Ethanol.
  36. 36. Yeast  abundant on sugary surfaces of ripe fruit  but can also be added
  37. 37. Grapes are crushed:  the sugar they contain is fermented by yeasts to produce alcohol & CO2. Industrial fermentation tanks.
  38. 38. What happens to CO2 during wine making? Escapes
  39. 39. What is the use of an ‘airlock? allows CO2 to escape prevents microbes from entering
  40. 40. Why does the balloon inflate? As yeast ferments the sugar, CO2 is released.
  41. 41. Question: MAY, 2004 The apparatus used to make wine was sterilised before being used. Why is sterilisation of the apparatus important? To kill bacteria as they can convert ethanol into ethanoic acid. Vinegar would be produced instead of wine.
  42. 42. Different varieties of grapes produce different types of wine
  43. 43. Question: MAY, 2012 Some winemakers add sucrose to unfermented grapes. What is the effect of this sucrose addition on the alcohol content of the wine produced? (1) Increase in alcohol content.
  44. 44. Question: SEP, 2007 1) Humans have used yeast to produce pizza dough. Describe briefly TWO other beneficial ways in which yeast has been utilised by human beings for economic benefits. (4) 2) Suggest TWO advantages and ONE disadvantage for yeast cells when included in these processes. (3)
  45. 45. Other uses of yeast: As SCP (single cell protein) In genetic engineering experiments
  46. 46. Question: SEP, 2012 Yeast is a fungus. a) Give ONE characteristic of fungi. (2) b) Name the type of asexual reproduction performed by yeast cells. (1) c) Give ONE disadvantage of asexual reproduction. (2)
  47. 47. THE END