Protists Chapter 28
Protists
Chapter 28
Protists
Eukaryotes Not plants, fungi or animals
Protists
Unicellular Colonial Multi-cellular Highly variableNo one unifying feature“protist” informal term Greatest diversity of eukaryotic kingdoms.
Endosymbiosis
Cyanobacterium
Heterotrophiceukaryote
Over the courseof evolution,this membranewas lost.
Red alga
Green alga
Primaryendosymbiosis
Secondaryendosymbiosis
Secondaryendosymbiosis
Secondaryendosymbiosis
Plastid
Dinoflagellates
Apicomplexans
Stramenopiles
Plastid
Euglenids
Chlorarachniophytes
General biology
Cell surfaceLocomotion organellesCyst formationNutrition Reproduction
Cell surface
Varies Only cell membraneExtra cellular material (ECM) on outside of membraneECM 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 extensionsFilopodia-thin branch extensionsAxopodia-supported by microtubules
Cyst formation
Protective coveringIn adverse environmentsDormant forms
Nutrition
Phototrophs (photosynthetic)HeterotrophsMixotrophs Combine photosynthesis with heterotrophic nutritionPhagotrophsIngest visible particles of foodOsomotrophsIngest soluble food
Reproduction
Asexually– Binary fission– Budding
Sexual reproductionGamete meiosisSpore-producing protists are haploid as adultsAlgae alternate haploid/diploid
Fig. 28-23
Commonancestorof alleukaryotes
DHFR-TSgenefusion
Unikonta
Excavata
Chromalveolata
Rhizaria
Archaeplastida
Choanoflagellates
Animals
Fungi
Amoebozoans
Diplomonads
Euglenozoans
Alveolates
Stramenopiles
Rhizarians
Red algae
Green algae
Plants
RESULTS
Categories
1. Excavata2. Chromalveolata3. Rhizaria4. Archaeplastida5. Unikonta
1. Excavata
DiplomonadsParabasalidsEuglenozoans
CDC
Diplomonads
Giardia lamblia (parasite)Flagellate protistMitochondria lacking DNA, ETC or enzymes for citric acid cycleAnaerobic environmentFound in waterCause diarrhea“hikers diarrhea”
Parabasalids
TrichomonadsReduced mitochondriaAnaerobic energy production T. vaginalisInfects vaginal liningDisrupts normal acidity of vagina
Euglenozoans
AutotrophsHeterotrophsParasites
Euglenozoans
EuglenoidsMixotrophs Earliest free-living eukaryotesFresh waterMove by flagellumAsexually
Euglena
Euglenozoan
KinetoplastidsSingle mitochondria2 types of DNAParasitesTypanosomiasis African sleeping disease
2. Chromalveoletes
Alevolates– Dinoflagellates– Apicomplexans– Ciliates
Stramenopiles– Diatoms– Golden algae– Brown algae– Oomycetes
Dinoflagellates
Alveolata
Common traitAlveoli (membrane sac) Space below plasma membraneDinoflagellatesApicomplexesCilliates
Dinoflagellates
PhotosyntheticMarine & freshwaterCharacteristic shapeReinforced 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 parasitesSpores pass from host to hostApical complexes:Organelles-one of cellPlasmodium causes malariaMosquito to human
Plasmodium
Malaria
Toxoplasma gondi
Ciliates
Large numbers of ciliaAnchored to microtubules below membrane2 nuclei Macronucleus for mitosisMicronucleus for sexual reproduction
Paramecium
Paramecium
Ciliates
Paramecium
Stramenopila
DiatomsBrown algaeGolden algaeOomycetes
Diatoms
Unique glasslike walls Hydrated silica in an organic matrix.Overlap like a shoe box & lid.PhotosyntheticMostly unicellular
Diatoms
Brown algae
Largest algae (kelp)MulticellularMost are marineFound in cooler watersColor due to carotenoids Alternate between diploid & haploid cyclesThickens foods (ice cream, pudding)
Brown algae
Golden algae (Chrysophyta),
Named for the yellow & brown carotene Xanthophyll pigmentsTypically bi-flagellated.Many freshwaterMost are unicellular, some are colonial.Poor environment;Form resistant cysts-viable for decades.
Golden algae (Chrysophyta),
Oomycetes
Cellulose in cell wallsMostly diploidFlagellated cellsCaused the potato blight in 1845-47Turned potato plants to black slime
3. Rhizaria
AmoebasForamsRadiolarians
Amoebas
PseudopodsFlowing extension of cytoplasmPulls amoeba forwardCauses 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 materialsHardened with calcium carbonateTests
Forams
Radiolarians
MarineInternal skeleton made of silicaSkeleton lines seafloor when dies
200 µm
Radiolarians
4. Archaeplastida
Red algaeGreen algae
Rhodophyta
Red algaeMicroscopic to large seaweed on beachMostly multi-cellularWarm coastal watersUsed in sushi
Red algae
Chlorophyta
Green algaeGreen chloroplastsSimilar to plantsDiverged recentlyMostly live in fresh waterUnicellular to multi-cellular
Green algae
5. Unikonta
Slime moldsChoanoflagellida
Slime molds
Looks like a moving mass of slimePlasmodiumA multinucleated mass of cytoplasmMove as a mass called a slugDigest bacteria, yeasts & other small organic particlesMulti-cellular & unicellular
Slim molds
Slim molds
Slim molds
Slim mold
Choanoflagellida
Similar to spongesFreshwaterSingle flagellumFeed on bacteria
Fig. 28-UN6