Protists

Question 1

What are protists?

Answer 1

Eukaryotes that don’t fit as typical animals, plants, or fungi

Question 2

What landscape are most protists found?

Answer 2

Aquatic

Question 3

Are protists usually uni- or multicellular?

Answer 3

Unicellular (however colonial and multicellular forms have evolved MANY times).

Question 4

What cell features does a protist usually (NOT ALWAYS) have?

Answer 4

1. unicellular
2. flagella
3. chloroplasts
4. cell wall or specialised cytoskeleton for internal support
5. live in colonies
6. Sexual/ asexual/ or both

Question 5

What do we call plant-like protists?

Answer 5

Algae - the functional term we use for anything that photosynthesises that is NOT a true plant

Question 6

What do we call animal-like protists?

Answer 6

Protozoa

Question 7

What do we call fungi-like protists?

Answer 7

Slime moulds

Question 8

What are the 4 supergroups (acknowledging that knowledge and theories are changing)?

Answer 8

1. Excavata
2. SAR clade
3. Archaeplastida
4. Unikonta

Question 9

Where is the hypothesised root of the eukaryotic tree located?

Answer 9

Between the unikonts and all other eukaryotes

Question 10

What type(s) of reproduction do protists do?

Answer 10

Asexual or sexual (for typical protists)

Question 11

Describe protist asexual reproduction.

Answer 11

1. Reproduction via mitosis
2. Used when conditions are good (have to put in less effort)

Question 12

Describe protist sexual reproduction.

Answer 12

1. Mature cell forms gametes.
2. Gametes together form zygotes
3. Zygotes remain in a cyst state until conditions are tright
4. Meiosis is completed

Question 13

What is a haploid?

Answer 13

Has 1 set of chromosomes

Question 14

What is a diploid?

Answer 14

Has 2x sets of chromosomes

Question 15

What is a dikaryotic?

Answer 15

2 haploid nuclei per cell

Question 16

How do many protists move?

Answer 16

Via flagella and/or cilia

Question 17

What are the main differences between flagella and cilia?

Answer 17

Flagella = long, one to few

Cilia = short, many!

Question 18

How to protists move if they don’t have flagella or cilia?

Answer 18

Pseudopodia

Question 19

What is pseudopodia?

Answer 19

Temporary arm-like projections of a cell’s membrane that help with movement, capturing food, and sensing the environment

Question 20

What nutritional profile do protists have?

Answer 20

1. Autotrophic (e.g. algae)
2. Or heterotrophic (e.g. protozoa, smile moulds)

Question 21

Explain primary endosymbiosis for protists.

Answer 21

1. A lineage of heterotrophic eukaryotes acquired an additional endosymbiont - a photosynthetic cyanobacterium
2. This evolved into plastids
3. The plastid bearing lineage gave rise to 2 lineages of photosynthetic protists (aka algae): red and green algae

Question 22

Explain the secondary endosymbiosis for protists.

Answer 22

1. Red and green algae were ingested in the food vacuoles of heterotrophic eukaryotes
2. Became endosymbionts themselves.

Question 23

What is a close relative of modern plants?

Answer 23

Green algae (especially charophytes) which can be unicellular, colonial, or multicellular

Question 24

What are 2 examples of parasitic protists?

Answer 24

1. Malaria
2. Giardia & Cryptosporidium

Question 25

What colonial protists may animals have evolved from?

Answer 25

Choanoflagellates (a group of free-living unicellular and colonial flagellate eukaryotes)

Question 26

What is an example of symbiotic protist?

Answer 26

1. Photosynthetic dinoflagellates - food-providing symbiont partners of the animals that build coral reefs 2. Wood digesting protists living in the guts of termites