2.3 - Protists

Question 1

Roles of protists in organisms/ecosystems

Answer 1

Protists that perform photosynthesis are the major producers in the world’s oceans. Non-photosynthetic protists are important consumers.

Also in food such as nori (sushi), agar (jelly), and carrageenan (red seaweed).

Question 2

Diseases caused by protists

Answer 2

Malaria (by Plasmodium) & beaver fever (by Giardia)

Question 3

Origin of Eukaryotes

Answer 3

Protists were the first. Mitochondria & chloroplasts are from endosymbiosis.

Endosymbiosis - where one type of cell lives in another type of cell. Mitochondria & chloroplasts were once prokaryotic, but were engulfed by an eukaryotic cell and incorporated into them.

Question 4

Protists characteristics

Answer 4

** Not animals, plants, or fungi

Metabolism - aerobic or anaerobic - photoautotrophs (use photosynthesis for food) & heterotrophic (eats animals and plants for food)

Most are unicellular, but some are multicellular

Question 5

Reproduction of protists (ex. Paramecia)

Answer 5

Unicellular protists reproduce asexually by binary fission

Multicellular protists reproduce sexually by conjugation

Question 6

Paramecium Characteristics

Answer 6

• Use cilia to move
• Vacuoles that contract to expel water

Question 7

Euglena Characteristics

Answer 7

• Use flagella to move
• Has chloroplasts

Question 8

Amoeba

Answer 8

• Hard, outer skeletons
• Move by extension of cytoplasm called pseudopods