Chapter 28: Protists Flashcards
1
Q
what is a protist
A
term used to refer to all eukaryotes that are not plants, animals, or fungi
2
Q
what do eukaryotic cells have
A
organelles
3
Q
the organims in most eukaryotic lineages are what
A
protists
4
Q
are most protists unicellular or multicellular
A
unicellular
5
Q
why are protists not considered a kingdom
A
because some protists are more closely related
to plants, fungi, or animals than other protists
6
Q
what do protists exhibit more than any other group of eukaryotes
A
structural and funcitnal diversity
7
Q
why are single-celled protists complex
A
carry out all functions of life
8
Q
what are some examples of cellular organization with membrane bound organlles
A
nucleus, golgi ap, ER, lysosomes
9
Q
what can protists be categorized in
A
photoautotrophs,(chloroplast), heterotrophs( absorb organic molecules or ingest large food particles), mixotrophs ( combine photoynthesis and heterotrophic nutrition
10
Q
how do protists reproduce
A
asexually, and some produce through meiosis
11
Q
where does protist diversity have its origins
A
endosymbiosis
12
Q
what is endosymbiosis
A
relationship between two species in which one organism lives inside the
cell or cells of the other organism (the host)
13
Q
where is the mitochondria and plastid derived from
A
bacteria (prok) that were engulfed by ancestors of early eukaryotes
14
Q
what did molecular analysis indicate about the evolution of mitochondira and plastid
A
evolved only once in the history of life
15
Q
what evolved first mitochondria or plastid
A
mitochondira
16
Q
how did mitochondria rise
A
alpha proteobacterium
gram negative bacteria
17
Q
evolution of mitochondira gave rise to what
A
eukaryotes
18
Q
how did plastids rise
A
a heterotrophic eukaryote engulfed a photosynthetic
cyanobacterium
19
Q
how many membranes do cyanobacteria, and plastids of red and green algae have
A
2
20
Q
what ingested the red and green algae themselves what is the process called
A
heterotrophic eukaryotes, secondary endosymbiosis
21
Q
what is a nucleomorph
A
the engulfed cell contains a vestigal nucleus
22
Q
what is the clade excavata characterized by
A
cytoskeleton
23
Q
excavates include what
A
protists with modified mitochondria
24
Q
what do exacavted memebrs have
A
feeding groove on one side of the body
25
what groups are excavates
three monophyletic
groups: the diplomonads, parabasalids, and
euglenozoans
26
what do both dipomonads and parabasalids have in common
- lack plastids
| - reduced mitochondira
27
diplomonads
- equal sized nuclei + multple flagella
| - many are parasites like giardia intestinalis
28
parabasalids
- reduced mitochondria called hydrogenosomes
| - trichomonas vaginalis ( sexually transmitted parasite)
29
what is a euglenozoans
diverse clade
including predatory heterotrophs,
photosynthetic autotrophs, mixotrophs,
and parasites
30
main feature of euglenozoa
e distinguishing the
clade is a spiral or crystalline rod
inside each flagella
31
what does euglenozoans include
kinetoplastids, and euglenids
32
kinetoplastids
single mitochondrion
containing an organized mass of DNA called a
kinetoplast
-Free-living species are consumers of prokaryotes
in freshwater, marine, and moist terrestrial
ecosystems
- trypanosoma: causes sleeping sickness in humans
33
what are euglenids
one or two flagella that emerge from a pocket at one end of the cell
- some species are mixotrophs that switch between autotrophic and heterotrophic modes,
depending on the environmental conditions
34
what is a highly diverse group of protists
SAR
35
what is SAR
monophyletic supergroup named for the first letters of its three major clades:
Stramenopiles, Alveolates, and Rhizarian
36
what group is the most controversial between the different protists
SAR
37
stramenopiles
```
-include some of the most
important photosynthetic organisms on
Earth
- hairy flagellum paired with smooth
- diatoms, oomycetes, brown algae
```
38
diatoms
```
-unicellular algae with a unique
two-part, glass-like wall of silicon dioxide
- major component of
phytoplankton and are highly diverse
-
```
39
why do scientists advocate to fertilize the ocean with iron
promote diatom blooms and
facilitate movement of CO2
to the bottom of the
ocean
40
what alage is the largest and most comples
brown algae
41
brown algae
- multicellular algae
| - species commonly known as seeweed
42
what produces the brown color of brown algae
Carotenoids in the plastids
43
plant like structures of brown algae
: the
rootlike holdfast, which anchors the alga, and a
stemlike stipe, which supports the leaflike blades
44
what helps keep brown algae structures near water's surface
filled, bubble-shaped floats to keep
| photosynthetic structures near the water surface
45
what does brown algae lack
true tissues and
| organs
46
brown algae is important to who
humans
| - laminaria are eating
47
what is the most complex life cycle
alteration of generations
48
what is alteration of generatoins
both haploid and diploid stages are multicellular
49
what is the diploid generation called
sporophyte; produces spores
50
haploid spores
develop into multicellular haploid
| gametophytes that produce haploid gametes
51
fertalization of gametes results in what
diploid zygote, which develops into a new sporophyte
52
how is laminaria different than others
Heteromorphic species, such as Laminaria, have
| structurally different gametophytes and sporophytes
53
what is isomorphic
gametophytes and
| sporophytes that look similar to each other
54
what does oomycetes include
water molds, white rusts, and
| downy mildews
55
why were oomycetes misidentified as fungi
due to their
multinucleate filaments that resemble fungal
hyphae
56
what are oomyctes cell walls composed of
cellulose rather than chitin (for fungi)
57
why are oomy. different from fungi
molecular analysis shows they are different
58
what are oomyctes more related to
plastid-bearing groups,
| but do not have plastids or perform photosynthesis
59
alveolates
membrane-enclosed
sacs (alveoli) just under the plasma
membran
60
Three clades included in the alveolates
Dinoflagellates
– Apicomlexans,
– Ciliates
61
dinoglagellates
- abundant in marine and freshwater plankton
- 2 flagella in armor like cellulose plates
- diverse group
-
62
what are toxic red tides caused by
dinoflagellate blooms bc of the carotenoids in their plastids
63
apicomplexans
- most are parasitres of an animal
| - serious human disease
64
how do apicomplexans spread
host as infectious cells
| called sporozoites
65
what is merozoite
infects red blood cell
66
what is sporozoites
infect liver cells
67
life cycles of apicomplexans
sexual and asexual stages and require two or more different hosts
68
what apicoplexan causes malaria
plasmodium
69
how many people die from malarie each year
200 million people
70
what can plasmodium do
change its surface proteins; avoid
| detection in the host immune
71
why are ciliates named
named for their use of cilia to move around and feed on bacteria or other protists
72
ciliates have 2 types of nuclei
micronuclei and large macronuclei, each cell has one or more copies of each type
73
macronuclei
multiple copies of the
| genome
74
micronuclei
may be diploid or haploid,
| depending on the life stage
75
what does genetic variation result from
conjugation
76
what is conjugation
two individuals
exchange haploid micronuclei
(without reproduction
77
what happens to the macronucleus during binary fission
dissolves
78
many species of rhizarians are what
amoebas
79
what are amoebas
protists that move and feed
using pseudopodia, extensions of the cell
surface
80
how are rhizarian amoebas different from other amoebas
hreadlike
pseudopodia. Non-amoeboid rhizarians
have flagella to move
81
3 clades of rhizarians
- radiolarians
- forams
- cercozoans
82
radiolarins
- delicate symmetrical skeleton
- pseudopodia and microtubules radiate
- cytoplasm covering microtubules engulf prey
that become attached to the pseudopodia
83
what are most radiolarians
marine organisms
84
what are forams named for
porous calcium carbonate shells, called tests
85
where do pseudopodia extend in the test
through the pores
86
how are forams nourished
photosynthetic activity of symbiotic algae
87
where do forams live
ocean and freshwater
88
how can researchers measure content in fossilized forams
use the magnisum content
89
what are cercozoans
amoeboid and flagellated protists
| that feed using threadlike pseudopodia
90
where are cercozoans found
marine, fresh water, and soil ecosystems
91
what are most cercozoans
heterotrophic parasites or predators
92
what is the paulinella chromatophora
cercozoan autotroph
with a unique photosynthetic structure called a
chromatophore
93
what are chlorarachinophytes
small group of mixotrophs
94
what are the closest relative to plants
red and green algae
95
what did ancient protist evolve into
red algae and green algae
96
plants are descended from what
green algae
97
what is the supergroup that includes red algae, green algae, and plants
archaeplastida
98
what is phycoerythrin and how does it affect algae
masks the green of chlorophyll giving red algae its color
99
how does color of red algae vary
varies from greenish-red in shallow
| - dark red or black in deep water
100
what is the largest red algae
seeweed, multicellular
101
reproduction in red algae
sexual and include alternation of generations
102
where is red algae common
costal waters or tropical oceans
103
which species of red algae are consumed by humans
-porphyra (nori) used to wrap sushi
104
what are green algae named for
green chloroplasts, which
are structurally and chemically similar to those found in
plants
105
what group does green algae form
paraphyletic group that includes:
| charophytes and chlorophytes
106
charophytes
algae most closely related to plants
107
where do chlorophytes live
in fresh water
108
how did algae become larger and have greater complexity
- formation of colonies
- formation of true multicelluar bodies
- repeated division of nuclei
109
unikons
include protists that are closely related to fungi and animals
110
2 major clades of unikons
Amoebozoans: tubulinids and relatives
– Opisthokonts: animals, fungi, and related
protists
111
amoebozoans
amoebas that
have lobe- or tube-shaped
-tubulinids,slime
molds, and entamoebas
112
slime molds/ mycetoxoans
once thought
to be fungi due to their spore-producing fruiting
bodies
113
slime mold lineages
plasmodial slime
| molds and cellular slime molds
114
tubulinids
```
diverse group of
amoebozoans with lobe- or tube-shaped
pseudopodia
- unicellular protists
-found in soil and freshwater and marine
- most are heterotrophic and consume bacteria
```
115
plasmodial slime molds
- brightly colored often yellow or orange
- form a large feeding mass called plasmodium
- plasmodium undivided by plasma membranes contains many diploid nuclei
116
cellular slime molds
multicellular
aggregates in which cells are separated by
plasma membranes
117
what does the feeding stage of cellular slime molds consist of
solitary cells
- food is low = cells form aggregate
- aggregate will form fruiting body
- cells in stalk of fruiting body die
118
what is Dictyostelium discoideum
a model organism
| for the studying the evolution of multicellularity
119
entamoeba
parasites of all classes of vertebrates and some invertebrates
120
humans host at least 6 species but which one is pathogenic
E. histolytica is pathogenic
121
what does
| E. histolytica cause
amoebic dysentery, the third-leading cause of death due to eukaryotic
parasites
122
opisthokonts
diverse group including animals, fungi, and several groups of protist
123
where are protists found
diverse aquatic and moist terrestrial environments
124
key roles of protists in their habitats
symbiont and that of producer
125
symbiotic protitst
- protists can benefit their host
| - protists can be parasites
126
photosynthetic protists
- producers that obtain energy from the sun to convert it to CO2
127
who are the main producers in aquatic communities
photosynthetic protists and
| prokaryotes
128
what happened to protists as the temp increased
Growth and biomass of photosynthetic protists has
| declined as sea surface temperature has increased
129
what do phytoplankton communites rely on
upwelling of cold nutrient rich water from below
