Protists Flashcards
what are the characteristics of protists?
-membrane enclosed nucleus - eukaryotes
-mitochondria and/or chloroplasts
-cytoskeleton
-uni or multicellular
what type of cell are protists?
eukaryotes
how do protists get nutrition?
-some are photosynthetic - algae
-some are heterotrophs - amoeba
some can be both - mixotrophy - euglenoids & dinoflagellates
what type of habitats do protists live in?
-variety of habitats, so many its hard to pin down
-most require water, so often found in moist environments
-some are parasitic so they live in a host
what type of movement do protists have?
-some have flagella or cilium
-9+2 microtubule arrangement: 9 fused outer microtubules, 2 unfused inner ones
how can protists reproduce?
-sexually, asexually, binary fission… varied per usual
what are the 3 big big groupings of protists and how are they classified?
protists can be grouped into 3 informal groups based on their likeness to other eukaryotes: fungus-like, animal-like, and plant-like
how did eukaryotes arise from prokaryotes? aka what is endosymbiosis
-prokaryotic cells, at one point, took in other unicellular organisms such as mitochondria and chloroplasts. these organisms proved to be useful to the host, so they stuck around
what are the 4 big supergroups of protists?
-excavata
-SAR clade
-archaeplastida
-unikonta
what is the supergroup excavata clade and how are they recognized?
-recognized through cytoskeleton arrangement & an “excavated” feeding groove on side of body
-can also be recognized by flagella structure
what are the diplomonadia & parabasala clades and what supergroup do they belong to? what is the standout organism of this clade?
-belong to excavata supergroup
-no plastids, modified mitochondria, anaerobic & parasitic
-standout organism: giardia intestinalis, causes diarrhea from stream water if the water is not boiled`
what is the clade euglenozoa, its traits, standout organism, and what supergroup does it belong to?
-belongs to excavata supergroup
-can be predatory, parasitic, or mixotrophs
-standout organisms:
-trypanosoma [causes sleeping sickness, can change protein structure to evade immune system]
-euglena [photosynthesize in the sun, become predatory heterotrophs at night]
what is the SAR clade supergroup and what is its name originated from?
-very diverse group, so many classified on their DNA data
-name means the 3 clades that make up this group:
Stramenopiles, Alveolates, & Rhizarians
what traits make up the stramenopile clade?
-“stramen opile” = straw hair = many fine projections on flagella
-store food in the form of a glucose polymer called laminarin
what are the standout organisms of the stramenopile clade?
diatoms: freshwater/marine organisms, can absorb a lot of CO2 encouraging algae blooms
golden algae: can exist as a colony of unicellular organisms that look like one big organism, photosynthetic or mixotrophic
brown algae: the big algae you can see, mostly marine
what traits make up the alveolata clade?
-contain membrane bound sacs called Alveoli, of which nobody knows what they do
-mixotrophic, found in a variety of habitats
what are the standout organisms of the alvolata clade?
-dinoflagellates: have two flagella that allow it to “spin,” are bioluminescent, and can cause shellfish poisoning
-apicomplexans: parasitic protists whose life cycle involves two hosts, includes the Plasmodium parasite that causes malaria, sexual & asexual life stages
-ciliates: have cilia that are used in motion or feeding, predate on bacteria or smaller protists
what are the traits of the clade rhizarian?
-contain threadlike pseudopods used for moving around
-many species are amoebas
what are the standout organisms of the rhizarian clade?
-foraminifera: have calcium carbonate shells, can be used to age sediment deposits
-radiolarians: have shells made of silica, have microtubule-reinforced pseudopods
-cercozoans: contain most of the pseudopod-feeding amoeba, mostly heterotrophs with one autotroph species
what traits make up the archaeplastida supergroup?
-monophyletic group originated from a common ancestor that ate a cyanobacteria - secondary endosymbiosis
what standout organisms are in the archaeplastida supergroup?
-red algae: mainly multicellular, all marine, have Phycoerythrin which allows them to absorb blue/green light
-green algae: ancestor of all plants, mostly freshwater, some marine, unicellular, colonial, or multicellular, some free living and some symbiotic, lots of variety
what traits make up the unikonta supergroup?
-not much… very diverse group, relationship between clades based on myosin proteins and some genome relations
what is the clade amoebazoan? what traits does it have and what supergroup does it belong to?
-belongs to unikonta
-has pseudopods to move and feed, includes amoebas and slime molds
what is the clade opisthokonts and what supergroup does it belong to?
-belongs to unikonta
-includes animals, fungi, and a small variety of protists to be mentioned in other chapters
