Protists

Question 1

what are the characteristics of protists?

Answer 1

-membrane enclosed nucleus - eukaryotes
-mitochondria and/or chloroplasts
-cytoskeleton
-uni or multicellular

Question 2

what type of cell are protists?

Answer 2

eukaryotes

Question 3

how do protists get nutrition?

Answer 3

-some are photosynthetic - algae
-some are heterotrophs - amoeba
some can be both - mixotrophy - euglenoids & dinoflagellates

Question 4

what type of habitats do protists live in?

Answer 4

-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

Question 5

what type of movement do protists have?

Answer 5

-some have flagella or cilium
-9+2 microtubule arrangement: 9 fused outer microtubules, 2 unfused inner ones

Question 6

how can protists reproduce?

Answer 6

-sexually, asexually, binary fission… varied per usual

Question 7

what are the 3 big big groupings of protists and how are they classified?

Answer 7

protists can be grouped into 3 informal groups based on their likeness to other eukaryotes: fungus-like, animal-like, and plant-like

Question 8

how did eukaryotes arise from prokaryotes? aka what is endosymbiosis

Answer 8

-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

Question 9

what are the 4 big supergroups of protists?

Answer 9

-excavata
-SAR clade
-archaeplastida
-unikonta

Question 10

what is the supergroup excavata clade and how are they recognized?

Answer 10

-recognized through cytoskeleton arrangement & an “excavated” feeding groove on side of body
-can also be recognized by flagella structure

Question 11

what are the diplomonadia & parabasala clades and what supergroup do they belong to? what is the standout organism of this clade?

Answer 11

-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`

Question 12

what is the clade euglenozoa, its traits, standout organism, and what supergroup does it belong to?

Answer 12

-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]

Question 13

what is the SAR clade supergroup and what is its name originated from?

Answer 13

-very diverse group, so many classified on their DNA data
-name means the 3 clades that make up this group:
Stramenopiles, Alveolates, & Rhizarians

Question 14

what traits make up the stramenopile clade?

Answer 14

-“stramen opile” = straw hair = many fine projections on flagella
-store food in the form of a glucose polymer called laminarin

Question 15

what are the standout organisms of the stramenopile clade?

Answer 15

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

Question 16

what traits make up the alveolata clade?

Answer 16

-contain membrane bound sacs called Alveoli, of which nobody knows what they do
-mixotrophic, found in a variety of habitats

Question 17

what are the standout organisms of the alvolata clade?

Answer 17

-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

Question 18

what are the traits of the clade rhizarian?

Answer 18

-contain threadlike pseudopods used for moving around
-many species are amoebas

Question 19

what are the standout organisms of the rhizarian clade?

Answer 19

-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

Question 20

what traits make up the archaeplastida supergroup?

Answer 20

-monophyletic group originated from a common ancestor that ate a cyanobacteria - secondary endosymbiosis

Question 21

what standout organisms are in the archaeplastida supergroup?

Answer 21

-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

Question 22

what traits make up the unikonta supergroup?

Answer 22

-not much… very diverse group, relationship between clades based on myosin proteins and some genome relations

Question 23

what is the clade amoebazoan? what traits does it have and what supergroup does it belong to?

Answer 23

-belongs to unikonta
-has pseudopods to move and feed, includes amoebas and slime molds

Question 24

what is the clade opisthokonts and what supergroup does it belong to?

Answer 24

-belongs to unikonta
-includes animals, fungi, and a small variety of protists to be mentioned in other chapters