Chp 5 Flashcards
What is a protist?
Any microbial eukaryote that is not a plant, animal, or fungus. Found in moist environments like lakes, ponds, and decaying organic matter.
Where are protists commonly found?
Worldwide in moist environments (lakes, ponds, streams, oceans, moist soil, beach sand, decaying organic matter).
What role do protists play in aquatic ecosystems?
Critical members of plankton, forming the basis of aquatic food chains.
Name three ways eukaryotic microbes reproduce.
Asexual (binary fission, budding, mitosis, spores), sexual (meiosis to generate spores), or both (e.g., algae, fungi, protozoa).
What is encysting in protozoa?
A motile trophozoite transforms into a hardy cyst to survive harsh conditions (e.g., desiccation, nutrient deficiency).
Is encysting a reproductive process?
No. One trophozoite forms one cyst, which later becomes one trophozoite.
Name two human-infecting members of Excavata.
Giardia lamblia,Trypanosoma cruzi,Trichomonas vaginalis.
Name two non-human-infecting members of Excavata.
Euglena species, free-livingTrypanosoma.
Name two human-infecting members of Chromalveolata.
Plasmodium(malaria), Balantidium coli, Toxoplasma.
Name two non-human-infecting members of Chromalveolata.
Paramecium, dinoflagellates (e.g.,Karenia brevis).
Name a human-infecting member of Amoebozoa.
Entamoeba histolytica, Acanthamoeba.
Name a non-human-infecting member of Amoebozoa.
Amoeba proteus.
How do Excavata, Chromalveolata, and Amoebozoa differ?
Excavata: Flagellates with an “excavate” depression (e.g.,Giardia).Chromalveolata: Ciliates, dinoflagellates, or apicomplexans (e.g.,Paramecium,Plasmodium).Amoebozoa: Move via pseudopods (e.g.,Amoeba).
Why is conjugation sexual inParameciumbut not in bacteria?
Parameciumexchanges micronuclei (meiosis + recombination), while bacteria transfer plasmids (no meiosis).
Compare Euglena and dinoflagellates.
Similar: Both phototrophic, flagellated, aquatic.Differences:Euglena: Mixotrophic, stigma, no toxins. Dinoflagellates: Marine, cause red tides, some produce toxins.
