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Protists

Protists. Eukaryotes w/o tissue level of organization as in animals, plants, and fungi. Generalizations. Most unicellular Organelles that are similar to eukaryote animals None have embryonic tissue layers as in animals. Classification of Protista:. Excavata Diplomonadida = Giardia

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Protists

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  1. Protists Eukaryotes w/o tissue level of organization as in animals, plants, and fungi

  2. Generalizations • Most unicellular • Organelles that are similar to eukaryote animals • None have embryonic tissue layers as in animals

  3. Classification of Protista: • Excavata • Diplomonadida = Giardia • Kinetoplastida = trypanosomes • Euglenida = Euglena • Alveolata & Chromista • Ciliophora = ciliates • Apicomplexa = gregarines, coccidians • Dinoflagellata = flagellates • Opalinida = Opalina

  4. Classification of Protista: • Rhizaria • Rhizopoda = amoebas • Actinopoda = radiolarians • Amoebozoa • Lobosea = amoebas • Opisthokonta • Chlorophyta = Volvox

  5. Support and Locomotion • Plasma membrane • Many have thickening = pellicle • Or a test • Pseudopodia, cilia, flagella

  6. Nutrition • Autotrophs = ? • Heterotrophs = ? • Or both • Saprobic = take in dissolved stuff • Holozoic = solid foods (food vacuole)

  7. Reproduction • Asexual and sexual • Complex = parasites • Binary fission

  8. Budding Yeast

  9. Sexual repro • Production of gametes and then fusion = syngamy • Isogamy = same size gametes • Anisogamy = one larger • Or conjugation

  10. Phylum Euglenida • Mostly freshwater, few marine, brackish • Usually in habitat w/decaying organic matter

  11. Support • Pellicle = protein under cell membrane • Stripes are seams in protein strips • Flexible

  12. Locomotion by flagella • Two flagella, one usually shorter

  13. Nutrition • 1/3 have chloroplasts • Positive phototaxis • Photoreceptor near base of anterior flagellum

  14. 2/3 euglenids w/o chloroplasts • = heterotrophs = phagocytosis • Others can lose chloroplasts and switch • Few parasitic forms • Saprotrophic = take in dissolved nutrients

  15. Euglenid reproduction • Asexual by longitudinal cell division

  16. Euglenida examples you need to know: • Euglena • Perinema

  17. Other Euglenida? • Phacus

  18. Other Euglenida? • + Astasia

  19. Phylum Kinetoplastida • Trypanosomes, etc. • ~ 600 species described • Some free-living • Trypanosomes strictly parasitic • Digestive tracts of invert’s, phloem of plants, blood of vert’s

  20. Trypanosoma cruzi life cycle: Chagas’

  21. Reduviid = assasin bug

  22. Other parasitic forms • Leishmania: transmitted by sandflies • Causes skin and mucous membrane infections in humans • T. gambiense, others = sleeping sickness • Tse-tse fly is intermediate host • Tryps get into blood, then lymphatics and CS fluid

  23. kinetosome kinetoplast nucleus Support, locomotion • Pellicle, glycoprotein protects outside • Flagella: single, against side of cell

  24. Nutrition • Mostly unknown in parasitic forms • Free-living spp. are heterotrophic; capture bacteria with flagellum

  25. Reproduction • Asexual by longitudinal binary fission, budding • Complex life cycles

  26. Kinetoplastida you need to know! • Leishmania

  27. Infection occurs when infected sandfly regurgitates infective promastigotes into the blood while feeding. The promastigotes are phagocytized by macrophages and transform into amastigotes. The amastigotes multiply by binary fission in the macrophages. The life cycle is continued when a sandfly feeds on an infected person and ingests the amastigotes in the macrophages.

  28. Leishmania • Amastigotes in blood

  29. Leishmania • Amastigotes in liver cells

  30. Trypanosoma lewisi • Trypomastigote in vert. blood (infective form)

  31. Phylum Ciliophora • ~ 12,000 described species • Common in benthic, planktonic communities • Freshwater, marine, brackish • Most are single celled

  32. Mutualistic symbionts • E.g., in goats, sheep • Feed on plant material • Some are parasites in fish gut, one in human gut

  33. Support, locomotion • Alveolar membrane system • Underlying fibrous layer = epiplasm • Cilia in rows; used in taxonomy • More flexible for locomotion than flagella • Beat in cone

  34. Ciliophora you need to know: • Didinium

  35. Ciliophora • Paramecium, Vorticella

  36. Ciliophora • Euplotes

  37. Ciliophora • Spirostomum

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