Introduction into Protists

Question 1

Reasons to study protists?

Answer 1

• Understand diversity of life
• Food chain
• Photosynthesis
• Mutualistic symbiosis with other organisms
• Understanding stress responses
• Models of multicellularity
• Predators and Prey
• Agents of disease

Question 2

Do protist make up little or much of the eukaryotic tree of life?

Answer 2

Very much of tree of life

Question 3

Who discovered protists?

Answer 3

Leeuwenhoek

Question 4

Define protists:

Answer 4

• Group based on general similarities but exhibit a wide range of morphologies, inhabit many different habitats
• Unrelated to plants, animal and fungi
• Widespread

Question 5

What do protists have in common with one another?

Answer 5

• Require a water-based environment (fresh/marine/snow/damp soil/animal gut)
• Undergo mitosis
• Require presence of oxygen
• Unicellular
• Motile

Question 6

How do protists differ?

Answer 6

• How they obtain nutrition

- How they move

Question 7

What are different ways in which protists can obtain nutrients?

Answer 7

• Phagocytosis
• Photosynthesis
• Absorption of nutrients
• Symbiosis

Question 8

What are different ways in which protists move?

Answer 8

• Pseudopodia
• Cilia
• Flagella

Question 9

Are zooxanthellae autotrophs or heterotrophs?

Answer 9

autotrophs

Question 10

Are Euglena autotrophs or heterotrophs?

Answer 10

Heterotrophs

Question 11

What are zooxanthellae?

Answer 11

Symbiotic dinoflagellate protists that live within hard or stony corals

Question 12

What does it mean for zooxanthellae to be autotrophs?

Answer 12

Produce all nutritional substances required for them to live

Question 13

How much do zooxanthellae provide of coral energy via photosynthesis?

Answer 13

80%

Question 14

What do zooxanthellae take up?

Answer 14

Nutrients released by corals metabolism such as Nitrogen and Carbons Dioxide

Question 15

What is Euglena?

Answer 15

• Single, motile, flagellum for movement
• Sense light using red “eye spot”
• Contain chloroplast

Question 16

What do Euglena feed on in the dark?

Answer 16

Other protists

Question 17

What shows extensive evidence of protists preying on other protists?

Answer 17

Fossil record

Question 18

What may have played a critical role in the diversification of eukaryotes?

Answer 18

Predation

Question 19

Why are protists considered all eukaryotes?

Answer 19

• Cells have nucleus and other membrane-bound organelles

- Most single-celled

Question 20

What was the last eukaryotic common ancestor?

Answer 20

Flagellated protist

Question 21

What are many of intracellular organelles of protists?

Answer 21

Flagellate or ciliate

Question 22

What are different morphologies of protists?

Answer 22

• Amoebae
• Flagellates
• Ciliates
• Cysts/Cocci
• Hyphae
• Diatoms

Question 23

Why is it difficult to classify just on morphology?

Answer 23

Some protists have different morphological stages dependent on life cycle and enviroment

Question 24

What has advances in DNA sequencing allowed?

Answer 24

Classification protists with greater preseason

Question 25

What are dinoflagellates?

Answer 25

- Marine/photosynthesis/free-living or endosymbionts - Two flagella (equatorial/longitudinal groove) - Amoeboid form - Primary producers of organic mater

Question 26

What can dinoflagellate endosymbionts with?

Answer 26

Coral

Question 27

What is dinoflagellate associated with?

Answer 27

Toxic red tides

Question 28

What are loboseans?

Answer 28

- Naked or testate form - Predators, parasites or scavengers - Heterotrophic - Phagocytes - Free living - Disease causing

Question 29

What are heteroloboseans?

Answer 29

Amoeboid organisms | Disease causing

Question 30

What disease does heterolobosean causes?

Answer 30

Brain eating amoeba

Question 31

What are ciliates?

Answer 31

- Possesses hair-like cilia (allow complex behaviours) - Complex cellular forms = contractile/digestive vacuoles - Two types of nuclei - Most heterotrophic

Question 32

What are euglenoids?

Answer 32

- Flagellate with universal paracrystalline rod - Mitochondria - Cell shape determined by spiralling strips of protein - Some photosynthetic with photoreceptors

Question 33

What are kinetoplastids?

Answer 33

- Unicellular, flagellate with unique paracrystalline rod - Mitochondrion = kinetoplast - Medically important vector-borne pathogens

Question 34

What are phaeophyta?

Answer 34

- Marine - Multicellular filaments - Sessile/planktonic form - Giant kelps - Important in industry (cosmetics/ice cream)

Question 35

What are diplomonads?

Answer 35

- Unicellular, posses mitosomes - Posses two nuclei of equal size - Multiple flagella - Disease causing

Question 36

What disease does giardiasis?

Answer 36

Giardia lamblia

Question 37

What are parabasilids?

Answer 37

- Parabasal body - Hydrogenosomes (anaerobic) - Genome lacks introns (2x size of human) - Disease causing

Question 38

What are diatoms?

Answer 38

- Unicellular (some associate with filaments) - Carotenoids give golden or brown colour - Only male gamete have flagella - Two-piece silica cell walls - Bilateral or radial symmetry - Synthesis aquatic, phytoplankton

Question 39

What are foramiferans?

Answer 39

- Plantonic or sessile - External, spiral shells or calcium carbonate or chitin - Branching pseudopods extend through shell apertures to form a sticky reticulate net - Contributor to lime stone

Question 40

What are radiolarians?

Answer 40

- Marine heterotrophs - Tests made up of silica - Thin, stiff pseudopods reinforced by microtubules - Radial symmetry - Largest unicells

Question 41

What are myxomycetes?

Answer 41

- Cellular slime moulds - Single celled haploid myxamoebae - Nutrient starvation = myxamoebae swarm to make pseudoplasmodium (multicellular) or slugs (migrate) - Produce stalk and sporangium

Question 42

What are apicocomplexans?

Answer 42

- Contains an apical complex that facilitate host invasion - All parasites - May complex life-cycles and multiple hosts

Question 43

What are many medically important pathogens?

Answer 43

Protists