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Ch 18: Protists

Ch 18: Protists. Protists . unicellular eukaryotic. Prokaryotes vs Eukaryotes. Classification. 115,000 species Major debate regarding how they should be classified “animal-like” = zooplankton or protozoans “plant-like” = phytoplankton . Endosymbiotic Theory.

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Ch 18: Protists

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  1. Ch 18: Protists

  2. Protists • unicellular • eukaryotic

  3. Prokaryotes vs Eukaryotes

  4. Classification • 115,000 species • Major debate regarding how they should be classified • “animal-like” = zooplankton or protozoans • “plant-like” = phytoplankton 

  5. Endosymbiotic Theory • It is believed that protists evolved from a symbiotic relationship between different types prokaryotic cells • Chloroplasts resemble cyanobacteria • Mitochondria resemble aerobic bacteria

  6. Endosymbiotic Theory 2

  7. Animal-like Protists • 4 phyla: • Ciliophora (ciliates) - Paramecium • Zoomastigina (zooflagellates) • Sporozoa – Parasitic - Plasmodium • Sarcodina - ameoba

  8. Phyla #1. Ciliophora – Ciliates • Covered in cilia used for locomotion and for directing food into the oral cavity • Most are free-living (not parasites)

  9. Ex: Paramecium

  10. Structure • 1. Pellicle – cell membrane and underlay (looks quilt-like) controls entry and exit from the cell • Embedded in the pellicle are the: 2. Trichocysts – spiny projectiles used for protection

  11. 3. Macronucleus – controls cell’s activities • 4. Micronucleus – used in conjugation to mix the genetic information

  12. 5. Gullet (mouth). Cilia move food particles to the end of the gullet where they enter the cell by endocytosis. This traps the food particles into FOOD VACUOLES. • The food vacuoles will fuse with LYSOSOMES (sacks of digestive enzymes) and be digested.

  13. ENDOCYTOSIS

  14. 6. Anal pore: Waste particles leave the cell by exocytosis at the ANAL PORE

  15. Exocytosis

  16. 7. Contractile Vacuoles • Paramecium live in FRESH water • Osmosis causes water to move into the paramecium • The contractile vacuole collects the extra water so that the paramecium doesn’t lyse

  17. Osmosis Review

  18. Reproduction • Like bacteria, paramecium reproduce mainly by BINARY FISSION

  19. Paramecium Sex • Again, like bacteria, paramecium will occasionally engage in conjugation – usually when they are stressed.

  20. Conjugation is not actually “reproduction” – it is a trading and mixing of genetic material but no new paramecium are formed. However, new combinations of genes are created in both partners

  21. Phyla #2: Zoomastigina • Called the zooflagellates since they all move around using FLAGELLA • Many are parasitic Trichomonas causes intestinal and veneral diseases in humans

  22. Giardia – causes “beaver fever”

  23. Phyla #3: Sporozoa • All produce spores • All are parasites • All non-motile • Ex: Plasmodium (causes malaria) 

  24. Sporozoa

  25. Plasmodium Life Cycle • 1. Spores transferred to humans through mosquito saliva • 2. Spores grow in liver and blood cells, causing them to lyse, releasing toxins (creates fever, chills)

  26. 3. Mosquitoes pick up Plasmodium in the blood when it bites the human • 4. Mosquitoes become infected with Plasmodium – eventually, spores form in the salivary glands and the parasite is passed on to a new human

  27. How to Avoid Malaria • 1. Don’t go where there are malaria outbreaks • 2. In areas where there is malaria, don’t get bit by mosquitoes • 3. Chloroquinine will destroy some Plasmodium spores • 4. Most often, countries with malaria try to control the mosquito host rather than the Plasmodium (insecticides and breeding ground removal)

  28. Phyla #4: Sarcodina • Use PSEUDOPODS to feed and move around

  29. Ameoba

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