Chapter 28: Protists Flashcards
What is a protist?
Any eukaryotic organism that is not an animal, plant, or fungus.
When did the oldest eukaryotic fossils appear?
2.1 billion years ago
Is the kingdom, Protista, monophyletic, paraphyletic, or polyphyletic?
Paraphyletic
What are the fundamental (basic) features of eukaryotes?
- Nucleus with nuclear envelope - Mitochondria, ER, cytoskeleton - Multicellular - Sexual reproduction - Several complex RNA polymerases - translation begins with methionine
The organisms in most eukaryotic lineages are _________.
protists
Most protists are _______________.
unicellular
True or False: Protists do not exhibit structural and functional diversity
False, they do so tremendously
True or False: All traits found in protists can be found in other organisms as well
True
What are the four supergroups of eukaryotes?
- Excavata 2. The ‘SAR’ Clade 3. Archaeplastida 4. Unikonta
What are the groups within Excavata?
- Diplomonads - Parabasalids - Euglenozoans
What are the groups within The ‘SAR’ Clade?
- Stramennopiles - Diatoms - Golden Algae - Brown Algae 2. Alveolates - Dinoflagellates - Apicomplexans - Ciliates 3. Rhizarians - Forams - Cercozoans
What are the groups within Archaeplastida?
- Red algae - Rhodohyta 2. Green algae - Ulothrix - Chlamydomonas - Pandorina - Spyrogyra - Volvox 3. Land plants
What are the groups within Unikonta?
- Amoebozoans - Slime molds - Tubulinids - Entamoebas 2. Opisthokonts
DNA resemblance between slime molds and fungi is a result of ____________ _____________.
Convergent evolution
Slime molds include two lineages, what are they?
- Plasmodial slime molds 2. Cellular slime molds
Slime molds make _________ ___________ to find food.
conscious decisions
What are tubulinids?
- Diverse group of amoebozoans with lobe/tube shaped pseudopodia - unicellular - heterotrophic - consume bacteria and other Protists
What are opisthokonts?
Extremely diverse group of eukaryotes including animals and fungi
In short, what does the supergroup Unikonta include?
Protists that are closely related to fungi and animals
What is the key characteristic of euglenozoans in the Excavates supergroup?
Spiral or crystalline rod flagella
What is the key characteristic of diplomonads and parabasalids in the Excavates supergroup?
Modified mitochondria For diplomonads, it’s called mitosomes For parabasalids, it’s called hydrogenosomes
What is the key characteristic of stramenopiles in The ‘SAR’ Clade supergroup?
Hairy and smooth flagella
What is a kinetoplast?
An organized mass of DNA
Euglenids lack cell walls, what do they have instead?
A pellicle, which is a protein band beneath the plasma membrane.
What is the key characteristic of green algae in the Archaeplastida supergroup?
Plant-type chloroplasts
What is the key characteristic of amoebozoans in the Unikonta supergroup?
Lobe-shaped or tube-shaped pseudopodia
Which supergroups include photosynthetic members?
Excavata, ‘SAR’ Clade, and Archaeplastida
What is the key characteristic of red algae in the Archaeplastida supergroup?
Phycoerythrin (photosynthetic pigment)
What is the key characteristic of rhizarians in The ‘SAR’ Clade supergroup?
Amoebas with threadlike pseudopodia
Define endosymbiont
A cell that lives within a host cell
What is the endosymbiotic theory?
Organelles within eukaryotic cells appeared as a result of endosymbiosis between prokaryotic endosymbionts and eukaryotic host cells.
- this explains how eukaryotic features evolved from prokaryotic cells
What is the key characteristic of alveolates in The ‘SAR’ Clade supergroup?
Membrane-enclosed sacs (alveoli) beneath the plasma membrane
In the endosymbiont theory, _____________ were engulfed into the ancestral prokaryote to form ancestral heterotrophic eukaryotes.
mitochondria (aerobic bacterium)
In the endosymbiont theory, _____________ were engulfed into the ancestral prokaryote to form ancestral photosynthetic eukaryotes.
plastids (photosynthetic bacterium)
Which supergroup is the most controversial?
SAR Clade
In short, what does the supergroup Excavates include?
Protists with modified mitochondria and unique flagella
In short, what does the supergroup Archaeplatida include?
The closest relatives of land plants (red and green algae)
How do Protists live as mutualists?
They establish mutualistic relationships with other organisms 1. Coral polyps rely on dinoflagellates do producing a significant amount of their food (dinoflagellates are considered endosymbionts here). Many corals require Protists in order to survive, otherwise they may undergo coral bleaching.
How do Protists live as parasites?
Symbiotic Protists thrive inside mosquitos and use them as a primary host. When a mosquito bites a human, the Protists transfer to the new secondary host. The Protist, Plasmodium, now infect the human and cause malaria.
Which supergroup contains bioluminescent organisms?
‘SAR’ Clade
In terms of cellularity, are excavates unicellular or multicellular?
All are unicellular
In terms of cellularity, is The ‘SAR’ Clade unicellular or multicellular?
It varies 1. Stramenopiles - diatoms are unicellular - golden algae are unicellular - brown algae are multicellular 2. Alveolates - dinoflagellates are unicellular - apicomplexans are unicellular - ciliates are unicellular 3. Rhizaria - forams are unicellular - radiolarins are unicellular
In terms of cellularity, are archaeplastidas unicellular or multicellular?
Red algae - multicellular Green algae - unicellular and multicellular
In terms of cellularity, are unikonta unicellular or multicellular?
Unikonta consists of animals and fungi, so it varies greatly.
