Protists Chapter 28

Protists Eukaryotes Not plants, fungi or animals

Protists Unicellular Colonial Multi-cellular Highly variable No one unifying feature “protist” informal term Greatest diversity of eukaryotic kingdoms.

Endosymbiosis Cyanobacterium Heterotrophic eukaryote Over the course of evolution, this membrane was lost. Red alga Green alga Primary endosymbiosis Secondary endosymbiosis Secondary endosymbiosis Secondary endosymbiosis Plastid Dinoflagellates Apicomplexans Stramenopiles Plastid Euglenids Chlorarachniophytes

General biology Cell surface Locomotion organelles Cyst formation Nutrition Reproduction

Cell surface Varies Only cell membrane Extra cellular material (ECM) on outside of membrane ECM makes a strong cell wall Diatoms shells of silica

Locomotion organelles Varies Flagella (1 or more) Several shorter called cilia Pseudopodial (false feet) Lobopodia-blunt extensions Filopodia-thin branch extensions Axopodia-supported by microtubules

Cyst formation Protective covering In adverse environments Dormant forms

Nutrition Phototrophs (photosynthetic) Heterotrophs Mixotrophs Combine photosynthesis with heterotrophic nutrition Phagotrophs Ingest visible particles of food Osomotrophs Ingest soluble food

Reproduction Asexually –Binary fission –Budding Sexual reproduction Gamete meiosis Spore-producing protists are haploid as adults Algae alternate haploid/diploid

Fig Common ancestor of all eukaryotes DHFR-TS gene fusion Unikonta Excavata Chromalveolata Rhizaria Archaeplastida Choanoflagellates Animals Fungi Amoebozoans Diplomonads Euglenozoans Alveolates Stramenopiles Rhizarians Red algae Green algae Plants RESULTS

Categories 1. Excavata 2. Chromalveolata 3. Rhizaria 4. Archaeplastida 5. Unikonta

1. Excavata Diplomonads Parabasalids Euglenozoans CDC

Diplomonads Giardia lamblia (parasite) Flagellate protist Mitochondria lacking DNA, ETC or enzymes for citric acid cycle Anaerobic environment Found in water Cause diarrhea “hikers diarrhea”

Parabasalids Trichomonads Reduced mitochondria Anaerobic energy production T. vaginalis Infects vaginal lining Disrupts normal acidity of vagina

Euglenozoans Autotrophs Heterotrophs Parasites

Euglenozoans Euglenoids Mixotrophs Earliest free-living eukaryotes Fresh water Move by flagellum Asexually

Euglena

Euglenozoan Kinetoplastids Single mitochondria 2 types of DNA Parasites Typanosomiasis African sleeping disease

2. Chromalveoletes Alevolates –Dinoflagellates –Apicomplexans –Ciliates Stramenopiles –Diatoms –Golden algae –Brown algae –Oomycetes

Dinoflagellates

Alveolata Common trait Alveoli (membrane sac) Space below plasma membrane Dinoflagellates Apicomplexes Cilliates

Dinoflagellates Photosynthetic Marine & freshwater Characteristic shape Reinforced by internal plates of cellulose. Two flagella sit in perpendicular grooves in the “armor” Produce a spinning movement “red tide” produced with large growth

Apicomplexes Spore forming parasites Spores pass from host to host Apical complexes: Organelles-one of cell Plasmodium causes malaria Mosquito to human

Plasmodium

Malaria

Toxoplasma gondi

Ciliates Large numbers of cilia Anchored to microtubules below membrane 2 nuclei Macronucleus for mitosis Micronucleus for sexual reproduction

Paramecium

Ciliates

Paramecium

Stramenopila Diatoms Brown algae Golden algae Oomycetes

Diatoms Unique glasslike walls Hydrated silica in an organic matrix. Overlap like a shoe box & lid. Photosynthetic Mostly unicellular

Diatoms

Brown algae Largest algae (kelp) Multicellular Most are marine Found in cooler waters Color due to carotenoids Alternate between diploid & haploid cycles Thickens foods (ice cream, pudding)

Brown algae

Golden algae ( Chrysophyta ), Named for the yellow & brown carotene Xanthophyll pigments Typically bi-flagellated. Many freshwater Most are unicellular, some are colonial. Poor environment; Form resistant cysts-viable for decades.

Golden algae (Chrysophyta),

Oomycetes Cellulose in cell walls Mostly diploid Flagellated cells Caused the potato blight in Turned potato plants to black slime

3. Rhizaria Amoebas Forams Radiolarians

Amoebas Pseudopods Flowing extension of cytoplasm Pulls amoeba forward Causes dysentery

Amoebas

Forams Almost all marine. Most live in sand or attach to rocks or algae. Some are in plankton. Multi-chambered, porous shells Consists of organic materials Hardened with calcium carbonate Tests

Forams

Radiolarians Marine Internal skeleton made of silica Skeleton lines seafloor when dies

200 µm Radiolarians

4. Archaeplastida Red algae Green algae

Rhodophyta Red algae Microscopic to large seaweed on beach Mostly multi-cellular Warm coastal waters Used in sushi

Red algae

Chlorophyta Green algae Green chloroplasts Similar to plants Diverged recently Mostly live in fresh water Unicellular to multi-cellular

Green algae

5. Unikonta Slime molds Choanoflagellida

Slime molds Looks like a moving mass of slime Plasmodium A multinucleated mass of cytoplasm Move as a mass called a slug Digest bacteria, yeasts & other small organic particles Multi-cellular & unicellular

Slim molds

Slim mold

Choanoflagellida Similar to sponges Freshwater Single flagellum Feed on bacteria

Fig. 28-UN6