Lecture 24 - Protists I (SI) Flashcards
Excavata
- characterized by cytoskeleton
- some have excavated feeding groove
What are the 3 groups of Excavata?
- diplomonads
- parabasids
- euglenozoans
Structure Excavata
Diplomonads: reduced mitochondria (mitozones) + 2 nuclei + multiple flagella
Parabasalids: reduced mitochondria (hydrogenozomes)
Euglenozoans: spiral/crystalline rod inside flagellum
Metabolism Excavata
Diplomonads: anaerobic biochemical pathways
Parabasalids: generate some energy (anaerobically)
Euglenozoans: everything (hetero/auto/mixotrophs, parasites)
Examples Excavata
Diplomonads: Giardia intestinalis
Parabasalids: Trichomonas vaginalis (yeast infections)
Euglenozoans: African sleeping sickness, Euglenids
Which Excavata lack mitochondria?
- diplomonads
2. parabasalids
What is the archaezoa hypothesis?
- false
- protists are derived from ancient eukaryotic lineages before the cquisition of endosymbiotic bacteria that evolved into mitochondria
What is the accepted theory about mitochondria in protists?
protists lost their normal mitochondria during their evolution
Alveolata
- supported by molecular evidence
- members have alveoli
What are alveolli?
- small membrane-bound cavities with unknown function
- may aid in cell surface/water/ion regulation
Euglenoids
characterized by an anterior pocket from which one or two flagella emerge
Kinetoplastids
have single large mitochondrion associated with a unique organelle (kinetoplast)
What are 3 groups in chromalvealata?
- Dinoflagellates
- Apicomplexans
- Cliates
Structure Chromalvealata
Dinoflagellates: cellular plats, 2 spinning flagella in perpendicular grooves, bioluminsecent
Metabolism Chromalvealata
Dinoflagellates: part of plankton or hetertrophic
Apicomplexans: anaerobic biochemical pathways
