Single celled eukaryotes


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Single celled eukaryotes

  1. 1. SINGLE CELLED EUKARYOTES Presented by- Hasnahana Chetia M.Sc BT IInd sem, G.U.
  2. 2. A eukaryote is an organism whose cells contain complex structures enclosed within membranes. The defining membrane- bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear envelope, within which the genetic material is carried.
  3. 3. The single celled eukaryotes are classified under the kingdom “PROTISTA”. It is a being a paraphyletic group. They are first eukaryotes, having a well organized nucleus and complex membranous organelles. Protozoa; some unicellular algae, phycomycetes; myxomycetes and yeasts come under this kingdom. The term protista was first used by Ernst Haeckel in 1866. The simplest protist is “Amoeba”.
  4. 4.  They are microscopical, unicellular eukaryotes.  They are unicellular or colonial forms without distinct division of labor.  They generally live in water.  They maybe heterotrophic or autotrophic.  They may use pseudopodia, flagella or cilia for locomotion.  They showed mitosis and meiosis.
  5. 5. There are four phyla of Animal-like Protists classified by how they move- 1.Zooflagellates – flagella. 2.Sarcodines - extensions of cytoplasm (pseudopodia). 3.Ciliates – cilia. 4.Sporozoans - do not move.
  6. 6. They move using one or two flagella absorb food across membrane, eg-Leishmania Fig. Leishmania
  7. 7. They moves using pseudopodia (false feet),which are like extensions of the cytoplasm --ameboid movement. They ingest food by surrounding and engulfing food (endocytosis),creating a food vacuole. They reproduce by binary fission. contractile vacuole - removes excess water can cause amebic dysentery in humans - diarrhea and stomach upset from drinking contaminated water
  8. 8. Fig. Amoeba Fig. Foraminiferan Fig. Heliozoa
  9. 9.  Paramecium- They move using cilia;has two nuclei: macronucleus, micronucleus;food is gathered through food vacuole;anal pore is used for removing waste;contractile vacuole removes excess water;reproduces asexually (binary fission) or sexually (conjugation);paramecia are always the same shape,like a shoe. Fig. Paramecium
  10. 10. They do not move on their own. They are parasitic. Plasmodium falciparum and Plasmodium vivax are sporozoans, infects the liver and blood and causes malaria. Fig. Plasmodium vivax
  11. 11.  They contain chlorophyll and carry out photosynthesis.  There are four phyla: euglenophytes, chrysophytes, diatoms, dinofla gellates.  Their accessory pigments help absorb light, and give them a variety of colors.
  12. 12.  Euglena- They live in water,have 2 flagella for movement,use chlorplasts for photosynthesis, but turn into heterotrophs if kept in the dark, has an eyespot used for sensing light and dark pellicle - like a cell wall, helps maintain their shapes. Fig. Euglena
  13. 13.  Chrysophytes- Yellow-green algae, "golden plants“.  Diatoms- produce thin cell walls of silicon.  Dinoflagellates- Often have two flagella luminescent. Fig. Chrysophytes Fig.Diatoms Fig. Dinoflagellates
  14. 14. Yeasts are eukaryotic, mostly unicellular micro- organisms.Most reproduce asexually by budding, although a few do so by mitosis. They are phylogenetically diverse and are placed under phyla Ascomycota and Basidiomycota. Yeasts are chemorganotrophs. They usually reproduce by budding or by meiosis and spore formation (under stress conditions).
  15. 15. Fig. Yeast
  16. 16. Nutrition in some different types of protists is variable. In flagellates, for example, filter feeding may sometimes occur where the flagella find the prey. Other protists can engulf bacteria and digest them internally, by extending their cell membrane around the food material to form a food vacuole. This is then taken into the cell via endocytosis usually phagocytosis; sometimes pinocytosis.
  17. 17. Nutritional type s Source of energy Source of carbon Examples Phototrophs Sunlight Organic compounds or carbon fixation Algae, Dinoflage llates or Euglena Organotrophs Organic compounds Organic compounds Apicomplexa, Tr ypanosomes or Amoebae
  18. 18. Some protists reproduce sexually (conjugation), while others reproduce asexually (binary fission). Some species, for example Plasmodium falciparum, have extremely complex life cycles that involve multiple forms of the organism, some of which reproduce sexually and others asexually.
  19. 19.  Protists form a broad base across the bottom of the food chain, and they supply approximately one-half of the world’s oxygen.  Protists, along with bacteria and fungi, are responsible for decomposing and recycling nutrients.  Euglena are used to help treat sewage because of their unique ability to switch from an autotrophic to a heterotrophic nutritional mode, helping to maintain oxygen levels in the balance.  Trichonympha which lives in the digestive system of termites and produces cellulase, an enzyme that enables termites to digest wood.  Products derived from protists are used in treatment of ulcers, high blood pressure and arthritis.
  20. 20. Some protists are significant pathogens of both animals and plants; for example Plasmodium falciparum and P. vivax, which causes malaria in humans, and Phytophthora infestans, which causes potato blight. Balantidium Coli and Entamoeba Histolytica causes severe dysentry in animals, eg-pigs and humans. Mastigophorites that belong to the genus trypanosoma,causes African Sleeping Sickness, a disease which often leads to death.
  21. 21.  tista.htm  d=20061030191849AA5001g   http://single%20celled%20euk/Introduction% 20to%20the%20Protists.htm   logyPages/P/Protists.html