Chapter 28: Protists

Question 1

What is a protist?

Answer 1

Any eukaryotic organism that is not an animal, plant, or fungus.

Question 2

When did the oldest eukaryotic fossils appear?

Answer 2

2.1 billion years ago

Question 3

Is the kingdom, Protista, monophyletic, paraphyletic, or polyphyletic?

Answer 3

Paraphyletic

Question 4

What are the fundamental (basic) features of eukaryotes?

Answer 4

• Nucleus with nuclear envelope - Mitochondria, ER, cytoskeleton - Multicellular - Sexual reproduction - Several complex RNA polymerases - translation begins with methionine

Question 5

The organisms in most eukaryotic lineages are _________.

Answer 5

protists

Question 6

Most protists are _______________.

Answer 6

unicellular

Question 7

True or False: Protists do not exhibit structural and functional diversity

Answer 7

False, they do so tremendously

Question 8

True or False: All traits found in protists can be found in other organisms as well

Answer 8

True

Question 9

What are the four supergroups of eukaryotes?

Answer 9

1. Excavata 2. The ‘SAR’ Clade 3. Archaeplastida 4. Unikonta

Question 10

What are the groups within Excavata?

Answer 10

• Diplomonads - Parabasalids - Euglenozoans

Question 11

What are the groups within The ‘SAR’ Clade?

Answer 11

1. Stramennopiles - Diatoms - Golden Algae - Brown Algae 2. Alveolates - Dinoflagellates - Apicomplexans - Ciliates 3. Rhizarians - Forams - Cercozoans

Question 12

What are the groups within Archaeplastida?

Answer 12

1. Red algae - Rhodohyta 2. Green algae - Ulothrix - Chlamydomonas - Pandorina - Spyrogyra - Volvox 3. Land plants

Question 13

What are the groups within Unikonta?

Answer 13

1. Amoebozoans - Slime molds - Tubulinids - Entamoebas 2. Opisthokonts

Question 14

DNA resemblance between slime molds and fungi is a result of ____________ _____________.

Answer 14

Convergent evolution

Question 15

Slime molds include two lineages, what are they?

Answer 15

1. Plasmodial slime molds 2. Cellular slime molds

Question 16

Slime molds make _________ ___________ to find food.

Answer 16

conscious decisions

Question 17

What are tubulinids?

Answer 17

• Diverse group of amoebozoans with lobe/tube shaped pseudopodia - unicellular - heterotrophic - consume bacteria and other Protists

Question 18

What are opisthokonts?

Answer 18

Extremely diverse group of eukaryotes including animals and fungi

Question 19

In short, what does the supergroup Unikonta include?

Answer 19

Protists that are closely related to fungi and animals

Question 20

What is the key characteristic of euglenozoans in the Excavates supergroup?

Answer 20

Spiral or crystalline rod flagella

Question 21

What is the key characteristic of diplomonads and parabasalids in the Excavates supergroup?

Answer 21

Modified mitochondria For diplomonads, it’s called mitosomes For parabasalids, it’s called hydrogenosomes

Question 22

What is the key characteristic of stramenopiles in The ‘SAR’ Clade supergroup?

Answer 22

Hairy and smooth flagella

Question 23

What is a kinetoplast?

Answer 23

An organized mass of DNA

Question 24

Euglenids lack cell walls, what do they have instead?

Answer 24

A pellicle, which is a protein band beneath the plasma membrane.

Question 25

What is the key characteristic of green algae in the Archaeplastida supergroup?

Answer 25

Plant-type chloroplasts

Question 26

What is the key characteristic of amoebozoans in the Unikonta supergroup?

Answer 26

Lobe-shaped or tube-shaped pseudopodia

Question 27

Which supergroups include photosynthetic members?

Answer 27

Excavata, 'SAR' Clade, and Archaeplastida

Question 28

What is the key characteristic of red algae in the Archaeplastida supergroup?

Answer 28

Phycoerythrin (photosynthetic pigment)

Question 29

What is the key characteristic of rhizarians in The 'SAR' Clade supergroup?

Answer 29

Amoebas with threadlike pseudopodia

Question 30

Define endosymbiont

Answer 30

A cell that lives within a host cell

Question 31

What is the endosymbiotic theory?

Answer 31

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

Question 32

What is the key characteristic of alveolates in The 'SAR' Clade supergroup?

Answer 32

Membrane-enclosed sacs (alveoli) beneath the plasma membrane

Question 33

In the endosymbiont theory, _____________ were engulfed into the ancestral prokaryote to form ancestral heterotrophic eukaryotes.

Answer 33

mitochondria (aerobic bacterium)

Question 34

In the endosymbiont theory, _____________ were engulfed into the ancestral prokaryote to form ancestral photosynthetic eukaryotes.

Answer 34

plastids (photosynthetic bacterium)

Question 35

Which supergroup is the most controversial?

Answer 35

SAR Clade

Question 36

In short, what does the supergroup Excavates include?

Answer 36

Protists with modified mitochondria and unique flagella

Question 36

In short, what does the supergroup Archaeplatida include?

Answer 36

The closest relatives of land plants (red and green algae)

Question 36

How do Protists live as mutualists?

Answer 36

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.

Question 37

How do Protists live as parasites?

Answer 37

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.

Question 38

Which supergroup contains bioluminescent organisms?

Answer 38

'SAR' Clade

Question 41

In terms of cellularity, are excavates unicellular or multicellular?

Answer 41

All are unicellular

Question 42

In terms of cellularity, is The 'SAR' Clade unicellular or multicellular?

Answer 42

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

Question 43

In terms of cellularity, are archaeplastidas unicellular or multicellular?

Answer 43

Red algae - multicellular Green algae - unicellular and multicellular

Question 44

In terms of cellularity, are unikonta unicellular or multicellular?

Answer 44

Unikonta consists of animals and fungi, so it varies greatly.