Protists Learning Target Objectives (I can …): Distinguish between types of protists based on their characteristics and types of movement. Label and describe protist anatomy (structure) and physiology (function). Identify parasitic protists, the diseases they cause, and the vectors involved in their spread. Compare/contrast the types of protists and list examples of each.

Vocabulary: Protozoa * Algae * Slime molds * endosymbiosis * eukaryote * pseudopodia * phagocytosis * exocytosis * contractile vacuoles * binary fission * cysts * amoeba * cilia * pellicle * trichocysts * macronucleus * micronucleus * oral groove * mouth pore * gullet * anal pore * conjugation * nonmotile * vector * algae * pyrenoids * thallus * phytoplankton * zooplankton * diatoms * bioluminescent * red tide * euglena * eye spot * fruiting bodies

Kingdom Protista: 3 Major Divisions (Subkingdoms) I. Protozoa – heterotrophic, may be parasitic, “animal-like”. Eat bacteria, algae, and other protists. II. Algae – autotrophic (photosynthesize), “plant-like”, includes seaweed. III. Slime Molds – heterotrophic, decomposers (detritivores), some are parasitic. All protists are eukayotic. Endosymbiosis – theory that eukaryotes evolved from prokaryotic parasites living inside other prokaryotes. The parasites eventually became organelles. mitochondria = parasitic bacteria chloroplasts = parasitic blue-green bacteria

I. Protozoans are divided into 4 phyla based on how they move. 1) Phylum Sarcodina – move by projecting cytoplasm outward. These projections are called pseudopodia (false feet). The pseudopodia are also used to surround food, creating a vacuole. This is a form of phagocytosis. Wastes leave the cell in reverse. A vacuole opens to the outside, releasing wastes. This is called exocytosis. Contractile vacuoles are used to pump out excess water for freshwater sarcodines. Reproduction is by binary fission (like mitosis) Cysts are formed by sarcodines for protection in unfavorable conditions. Ex: Amoeba

2) Phylum Ciliophora – move by cilia (short, hair-like projections that wave like tiny oars). These may cause twisting motion too. Pellicle – rigid outer membrane Trichocysts – capsules containing barbed structures that can be projected from just below the surface for defense. Macronucleus – controls cell respiration, protein synthesis, digestion, and asexual reproduction. Micronucleus – controls sexual reproduction (genetic variability) Ex: Genus Paramecium has an oral groove with cilia sweeping food into this mouth-like structure and into the mouth pore (an opening). From here, food is put into vacuoles at the gullet and then the vacuoles float around in the cytoplasm delivering nutrients. Undigested food leaves the paramecium as vacuoles reach the anal pore.

Reproduction is usually asexual (binary fission) but may be (similar to) sexual reproduction. Sexual reproduction involves sharing genetic material with another paramecium. Eventually each paramecium splits in two. This process is known as conjugation. No eggs or sperm are produced (no meiosis). Therefore it is NOT true sexual reproduction. Other ciliophora – paramecium, vorticella, Didinium (barrel-shaped) and Balantidium.

3) Phylum Zoomastigina or Mastigophora Move by long, whip-like flagella (may have more than one) that push or pull them through water. (Many parasites in this group.) Flagellates include: Trypanosomes (African Sleeping sickness) Leishmania, Giardia, Trichomonas (STD) 4) Phylum Sporozoa - nonmotile (can’t move on their own), ALL are PARASITIC, spore forming, require 2 hosts to complete their life cycle. Spore form during asexual reproduction. Sporozoa include: Toxoplasma, Plasmodium (malaria)

Diseases Caused by Protozoans Entamoeba histolytica – (amoebic dysentery) Bloody diarrhea & even death May penetrate the intestinal lining Many amoeba live in our mouths and intestines Balantidium coli – (ciliate) Infects pigs, monkeys/apes, man Bloody diarrhea Worst if person has low stomach acid Trypanasoma gambiense & T. rhodesiense – (flagellates) Cause African sleeping sickness Infect the brain Transmitted by tsetse fly

Trypanosoma Cruzi - (flagellate) - Causes Chagas disease (South America) - Damage to the heart causes death - Transmitted by the Reduviid bug (kissing bug) which usually bites near the eyes. Giardia lamblia – (flagellate) - Infects intestines, can cause “greasy” diarrhea, and/or malnutrition. - “Don’t drink the water” – cysts are spread through water; chlorine doesn’t kill it but boiling water will. - Found even in Wisconsin streams, lakes, etc. Trichomonas vaginalis – (flagellate) - infects genitalia/reproductive tract - Usually no symptoms but can cause abdominal pain, increased bleeding, etc. - Spread by sexual contact OR moist surfaces

Toxoplasma gondii – (sporozoa) - causes stillbirths, mentally retarded babies, or visual problems in babies born to infected mothers - Infection usually occurs from ingesting or inhaling an oocyst - spread through cat feces. Pregnant women should stay away from litter boxes. Plasmodium sp. – (sporozoa) - causes malaria - chills, high fevers, liver & kidney damage & possible death - infection occurs in Red Blood Cells (RBCs) - Every 2-3 days, spores burst the RBCs, releasing toxins, creating the above symptoms, & causing anemia - Fevers are so high that they were used to kill syphillis & possibly Lyme disease organisms BUT malaria itself is becoming resistant to treatment. - Spread by Anopheles mosquito Vector – an organism that spreads or “carries” a parasite from 1 host to another

II. Algae (plant-like protists) - autotrophs with chloroplasts Pyrenoids – organelles that synthesize (make) & store starch - require moisture to reproduce - many have flagella Thallus – body of alga Phytoplankton – aquatic, unicellular algae eaten by fish. etc., produce oxygen (zooplankton – protozoans living in aquatic areas, eaten by fish, etc.) 6 Divisions of Algae 1) Chlorophyta – green algae - chlorophyll a & b - store food as starch - cellulose cell walls These 3 characteristics are the same for plants. These are most likely the ancestors of plants. Includes: spirogyra, chlamydomonas (STD), Volvox

2) Phaeophyta – brown algae - fucoxanthin pigment - large and multicellular - produce substance used in food gels - usually anchored to seafloor 3) Rhodophyta – red algae - contain phycobillins & chlorophyll a & d - some make up part of coral reefs with their cell walls - some make “carageenan” used in cosmetics, gelatin capsules, some cheeses, ice cream, and agar 4) Chrysophyta – golden brown algae - diatoms - shells with silica do NOT decompose - they’re used in swimming pool filtration, detergents, paint removers, insulators, etc - produce bulk of world’s oxygen

5) Pyrrophyta – “fire algae” or dinoflagellates - many are bioluminescent (make their own light) - red tide – USUALLY due to large “blooms” of dinoflagellates. Toxins produced can cause respiratory paralysis if infected fish, mussels, etc. are eaten. 6) Euglenophyta – Euglena - partly autotrophic & partly heterotrophic (when in the dark) - contain chlorophyll a & b - sometimes considered protozoans - flagella used for movement - eyespot detects light - contractile vacuole pumps out freshwater

Slime Molds Have 2 stages: a) reproductive stage – resemble fungi in this stage (similar reproductive structures) b) feeding stage – here they look & act like amoebas. Feed on decaying material. 2 Types of Slime Molds: 1) Plasmodial Slime Molds - have many nuclei scattered throughout cytoplasm - fruiting bodies release spores (to reproduce). These look like amoebas. When 2 unite, a new plasmodium develops. 2) Cellular Slime Molds - 1 nucleus per cell - group together when food is scarce but keep individuality