Amoeba & chlorella


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Amoeba & chlorella

  2. 2. PROTIST KINGDOM includes unicellular organisms e.g. Animal-like organisms - Amoeba Algae - Chlorella
  3. 3. Chlorella: a unicellular green algalives in stagnant water Chlorella cell dividing.
  4. 4. Chlorella structure nucleus cell wall nucleolus cell membrane cytoplasm chloroplast (cup-shaped) Pyrenoid(a collection of starch grains)
  5. 5. Chlorella feeds: autotrophically  builds the food itself by photosynthesis uses:  carbon dioxide to make sugar  water
  6. 6. Humans add Chlorella to their food  rich in proteins
  7. 7. Amoeba a unicellular animal-like organism lives in stagnant waterGive two functions of pseudopodia (‘false feet’). Pseudopodia
  8. 8. Functions of pseudopodia:1. moving2. feeding
  9. 9. Amoeba
  10. 10. AmoebaPART LABEL FUNCTION A endoplasm it houses all the cells organelles B ectoplasm since in a gel state it protects the cell C contractile vacuole it expels excess water from the cell D pseudopodium plays a role in locomotion and food capture controls movement of substances into and out of the E cell membrane cell F food vacuole digests engulfed food G nucleus controls activities of the cell
  11. 11. Holozoic nutrition in Amoeba1 2 3 Amoeba Pseudopodia The food is enclosed senses food. surround the food. in a food vacuole (food + water). 5 64Enzymes from the Food is digested and cytoplasm are soluble materials are Undigestedsecreted into the absorbed and waste is food vacuole. assimilated (used up). expelled.
  12. 12. Amoeba reproduces asexually by splitting into two: binary fission
  13. 13. Osmoregulation in Amoeba Osmoregulation:  controlling the amount of water in the organism  is carried out by the contractile vacuole Contractile vacuole pumps out water.
  14. 14. Osmoregulation in Amoeba 1 Water enters the Amoeba by osmosis and collects in the contractile vacuole. 2 The contractilevacuole swells up. 4 The process starts all over again. 3 The contractile vacuolebursts to release the water.
  15. 15. Paramecium: two fixed contractile vacuolesContractile vacuoles
  16. 16. Marine amoebae do notpossess a contractile vacuole. Explain. Marine Amoeba Freshwater AmoebaMarine amoeba: same concentration as sea water. No excess water enters into them.
  17. 17. Question: MAY, 2010Give a biological explanation for the followingstatement:Single-celled organisms such as theParamecium need a contractile vacuole. (5) Contractile vacuole removesexcess water to avoid bursting of the organism.
  18. 18. Amoeba does not need aspecialised respiratory surface. Why? Amoeba is small, and so it has a large surface area to volume ratio this means that oxygen can diffuse from all over the cell membrane and reach all parts of the amoeba quickly
  19. 19. Gaseous exchange in Amoeba occurs by:  diffusion across the cell membrane Why does O2keep on entering? Why does CO2 move out all theGases move down their time?concentration gradient.