Diversity of Protists Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Eukaryotes:

A

protists, plants, animals, fungi
Have membrane-bound organelles
• Have a nucleus
• Have a cytoskeleton for support (Allows for asymmetrical cell forms)
4 supergroups within Eukarya (2 unresolved protistan group)
most are single celled organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Protists

A

are the most abundant eukaryotic lineages and are unicellular

Some can exist in colonies or be multicellular

Diverse reproductive cycles
Asexual, sexually, alternating between 2N and N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the nutritional modes in protists

A

Diverse nutritional modes:
Photoautotrophs, containing chloroplasts
Heterotrophs
Mixotrophs, both photosynthetic and heterotrophic( Have arisen independently in protist lineages )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain how the endomembrane system and plastids evolved in the evolution of eukaryotes.

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Compare primary and secondary endosymbiosis.

a. Identify the number of separate genomes in organisms with plastids.

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the basic characteristics of each of the four Supergroups.
a. Classify protists into one of the Supergroups or smaller clades (see list of names at the end of this document) based on present characteristics.

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Supergroup

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Heterotroph

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Autotroph

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Mixotroph

A

both photosynthetic and heterotrophic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Endomembrane system

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Primary endosymbiosis

A

engulfing of a photosynthetic cyanobacterium by a heterotrophic eukaryote

First transfer of photosynthesis from a prokaryote to a eukaryote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Secondary endosymbiosis

A

heterotrophic eukaryote ate a photosynthetic eukaryote

Usually a red or green algae
Spread photosynthesis to 3 out of 4 supergroups
Photosynthetic eukaryote becomes the new plastid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Plastid

A

is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracelluar endosymbiotic Cyanobacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Nucleomorph

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Phytoplankton

A

diatom
subgroup Stramenopiles
supergroup SAR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Zooplankton

A

Unicellular organisms that move via cilia
cilliates
subrgoup alveolates
supergroup SAR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Accessory pigment

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Macronucleus

A
transcriptional active (produces RNA)
in cilliates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Micronucleus

A

exchange of genetic material during conjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Pseudopodia

A

false feet

in rhizorans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Alga

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Amoeba

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Plasmodium (syncytium)

A

parasite that causes malaria

subgroup; apicomplexan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Colonial

A

i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Endosymbiosis

A

is a symbiotic relationship where one thing lives inside another

27
Q

Examples of Endosymbiosis

A

Mitochondria used to be a heterotrophic, O2 using prokaryote
All derived from a common ancestor
Chloroplasts used to be a photosynthetic prokaryote
• Arose multiple times

28
Q

Name the supergroups of eukaryotes?

A
4 supergroups 
Excavata 
SAR 
Archaeplastida  
Unikonts
29
Q

Supergroup Excavata

A

Excavates have an “excavated” feeding groove, based on cytoskeletal morphology

30
Q

What are the monophyletic clades of Excavata?

A

3 monophyletic clades:
• Diplomonads
• Parabasalids
• Euglenozoans

31
Q

Describe the Diplomonads

A

Mitochondria: mitosomes (lack functional ETC)

Metabolism: anaerobic pathways

Nutritional Mode: parasites (ex; giardia intestinalis beaver fever)

NUclei; 2 equal sized

Flagella: Multiple
Other features:

32
Q

Describe the Parabasalids

A

Mitochondria: reduced called hydrogenosomes

Metabolism: anaerobic releasing H as by product

Nutritional Mode: parasite (ex; Trichomonas vaginalis STI)

NUclei

Flagella: 2

Other features: undulating membranes

33
Q

Describe the Euglenozoans

A

Mitochondria: Single, large (Kinetoplastids)

Metabolism: *

Nutritional Mode: Predatory heterotrophs, autotrophs, mixotrophs, parasites

Nuclei: *

Flagella: Crystalline rod inside one of their flagella

Other features: Light detectors (Euglenids)

34
Q

Supergroup SAR

A

Very large group defined by DNA similarities (biggest and most diverse)
(Excavata was based on morphology )

35
Q

What are the 3 monophyletic clades of SAR?

A

Stramenopiles
Alveolates
Rhizarians

36
Q

What is included in the clade Stramenopiles?

A

Diatoms
Brown algae
Oomcyetes

37
Q

What is included in the clade Alveolates ?

A

Dinoflagellates
Apicomplexans
Ciliates

38
Q

What is included in the clade Rhizarians ?

A

Forams
Radiolarians
Cercozoans

39
Q

What are the diagnostic features of subgroup Stramenopiles?

A

2 flagella

1 with hairlike projections 1 smooth

40
Q

What are the diagnostic features of subgroup Alveolates?

A

Membrane bound sac (Alveoli) under the plasma membrane

41
Q

What are the diagnostic features of subgroup Rhizarians?

A

Amoebas and flagellated protists with pseudopodia

42
Q

Diatoms

A

subgroup Stramenopiles

Unicellular algae with a silica covering made of two pieces

~10,000 species

Phytoplankton

Main cause of shellfish poisoning due to the toxins they produce

Can result in huge “blooms”

43
Q

Brown Algae

A

subgroup Stramenopiles

Multicellular, mostly marine “seaweeds’

Alternation of generations life cycle (plant life cycle)

Brown due to carotenoids (accessory pigment) in their plastids

Have specialized structures such as
Holdfasts – anchorage
Stipe – “stem”
Blades – “leaves”

Above arose independently from similar features in plants -> analogous structures

Golden algae and oomycetes (used to be called water moulds(fungal but new molecular evidence found they look more like protists) are also included in this group

44
Q

Dinoflagellates

A

Subgroup Alveolates

Cells are reinforced by cellulose plates (groove in the middle)

Contains 2 flagella within grooves (they spin when they move)

Photoautotrophic (through secondary endosymbiosis),
mixotrophic and heterotrophic aquatic organisms

Causes “red tide”, blooms in the ocean

Can produce toxins

45
Q

Apicomplexans

A

Subgroup Alveolates

Unicellular parasites of animals

Contains sporozoites, specialized cells that invade host cells

Ex. Plasmodium, parasite that causes malaria

Have complex life cycles with asexual and sexual stages and which require 1-2 hosts

46
Q

Ciliates

A

Subgroup Alveolates

Unicellular organisms (zooplankton) that move via cilia

Most are predators that feed on bacteria and algae

Have 2 nuclei:
Micronucleus -> exchange of genetic material during conjugation
Macronucleus -> transcriptional active (produces RNA)

Reproduce via binary fission

47
Q

Radiolarians

A

Subgroup Rhizarians

Have delicate, symmetrical internal silica skeletons

Pseuodpodia(thin) radiate from central body

Mostly marine

48
Q

Foraminiferans(Forams)

A

Subgroup Rhizarians

Name means “little hole” for their porous shells (tests)

Made of calcium carbonate

Pseudopodia extend through the pores for moving, feeding, and building the shell

Aquatic, both marine and freshwater

90% of all forams are known from fossils

49
Q

Cercozoans

A

Subgroup Rhizarians

Amoeboid and flagellated protists

Common in marine, freshwater and soil ecosystems

Heterotrophs (most) and parasites (many) and predators

50
Q

Describe the Supergroup Archaeplastida

A

Composed of red algae, green algae and land plants

Monophyletic clade

common ancestor is an ancient protist that engulfed a cyanobacterium

51
Q

Red Algae

A

~600 species, red due to accessory pigment phycoerythrin (allows it to absorbs blue or green light)

Absorbs blue and green light

Most abundant large algae in tropical marine habitats

Multicellular, still considered “seaweeds”

Commonly eaten as a food source (Nori in sushi)

52
Q

Green Algae

A

~7000+ species

Single-celled and multicellular

Green due to chlorophyll in their chloroplasts

Paraphyletic group:
Chlorophytes -> mostly freshwater and terrestrial species
• Can be unicellular, multicellular and/or colonial
Charophytes -> closely related to land plants (next topic)

53
Q

Describe the Supergroup Unikonts ? what are the2 major clades

A

Includes animals, fungi, and some protists

Two major clades:
Amoebozoans
Opisthokonts

Each clade is supported by molecular systematics and analysis of myosin proteins

However, we don’t know the root of the Eukaryotic tree at the Unikonts
• We don’t know which group of Eukaryotes came first

54
Q

What do the Amoebozoans include?

A

Slime Moulds
Tubulinids
Entameobas

55
Q

what do the Opisthokonts include?

A

Nucleariids
Fungi
Choanoflagellates
Animals

56
Q

Amoebozoans

A

Includes amoebas with lobe or tube-shaped pseudopods

57
Q

What 2 forms do slime moulds occur in?

A

Plasmodial slime moulds

Cellular slime moulds (single cell)

58
Q

Slime Moulds

A

( Mycetozoans,formerly Myxomycota)

Produce fruiting bodies that aid in spore dispersal

But no longer considered fungi -> convergent evolution

59
Q

Plasmodial slime moulds

A

Form a mass called plasmodium (syn. syncytium), a single- celled cytoplasm containing many nuclei

Produced via mitosis that does not end in cytokinesis

Extends pseudopodia through substrate to feed (phagocytosis)

When environment dries, stops expanding and produces sporangia

60
Q

Cellular slime moulds

A

Feeding stage consists of solitary cells but join together when food is depleted, forming aggregated amoebas that produce stalked sporangia for spore dispersal

61
Q

Tubulinids

A

Unicellular protists found in soil and aquatic environments

Most are heterotrophs, eating bacteria and other protists

Ex Amoeba proteus

Free-living

62
Q

Entamoebas

A

Parasites, infecting vertebrates

Ex. Entamoeba histolytica causes amoebic dysentery, which is spread by contaminated water

63
Q

What 2 groups remain uncertain and why?

A

There are two major groups of protists that remain uncertain

So hard to isolate and culture, grouping them based on morphology and/or DNA is near impossible
• Haptophytes
• Cryptomonads

64
Q

What is the strongest evidence of the EST?

A
Residual nuclei (nucleomorphs) are strongest evidence of EST 
Rhizaria and cryptonomads