Question 1

Which of the following statements best describes the process of secondary endosymbiosis in protist evolution?

Accepted Answer

A eukaryotic cell engulfs another eukaryotic cell that has already undergone primary endosymbiosis, resulting in a plastid with more than two membranes.

Question 2

Which of the following protist groups is classified under the SAR supergroup and is responsible for causing malaria in humans?

Accepted Answer

Apicomplexans

Question 3

A scientist discovers a unicellular organism with two nuclei, multiple flagella, and no functional mitochondria. To which group does this organism most likely belong?

Accepted Answer

Diplomonads (Excavata)

Question 4

Which of the following best explains why red algae and green algae are classified in the Archaeplastida supergroup?

Accepted Answer

They both descended from a common ancestor that acquired a chloroplast through primary endosymbiosis.

Question 5

Which of the following is a key difference between the life cycles of plasmodial slime molds and cellular slime molds?

Accepted Answer

Plasmodial slime molds form a multinucleate, diploid plasmodium, while cellular slime molds aggregate as individual haploid cells.

Question 6

Which of the following protist groups is most closely related to land plants?

Accepted Answer

Charophytes

Question 7

A patient is diagnosed with a disease caused by Plasmodium. Which stage of the Plasmodium life cycle is injected into the human host by a mosquito?

Accepted Answer

Sporozoite

Question 8

Which of the following statements about protist cellularity and reproduction is correct?

Accepted Answer

Protists can be unicellular, multicellular, or colonial, and may reproduce both sexually and asexually.

Question 9

Which of the following is a defining feature of the Euglenozoans within the Excavata supergroup?

Accepted Answer

The presence of a crystalline rod inside their flagella

Question 10

A marine biologist observes a protist with a glass-like cell wall composed of silica and a unique pattern of pores. This organism is most likely a member of which group?

Accepted Answer

Diatoms (Stramenopiles)

Question 11

Which of the following best describes the evolutionary significance of secondary endosymbiosis in protists?

Accepted Answer

It allowed certain protist lineages to acquire plastids with three or four membranes, increasing their metabolic diversity.

Question 12

Which of the following groups is NOT classified under the SAR supergroup?

Accepted Answer

Euglenids

Question 13

Which of the following is a characteristic feature of the Alveolates?

Accepted Answer

They possess membrane-bound sacs (alveoli) just under the plasma membrane.

Question 14

Which of the following best describes the relationship between animals, fungi, and certain protists within the eukaryotic supergroups?

Accepted Answer

They are all classified within the Opisthokonts, a subgroup of Unikonta.

Question 15

A protist is observed to have threadlike pseudopodia and a shell made of calcium carbonate. To which group does it most likely belong?

Accepted Answer

Forams (Rhizarians)

Question 16

Which of the following statements about the life cycle of Plasmodium is correct?

Accepted Answer

The sexual phase occurs in the mosquito, while the asexual phase occurs in the human host.

Question 17

Which of the following is true regarding the haploid and diploid stages in the life cycle of a cellular slime mold?

Accepted Answer

The individual amoeboid cells are haploid, and the zygote formed after fusion is diploid.

Question 18

Which of the following best explains why plants are not considered protists, even though they are classified within Archaeplastida?

Accepted Answer

Plants are multicellular, have specialized tissues, and undergo alternation of generations, distinguishing them from protists.

Question 19

Which of the following is a real-world example of the ecological importance of diatoms?

Accepted Answer

They are major primary producers in aquatic ecosystems, contributing significantly to global oxygen production.

Question 20

Which of the following protist groups is known for causing harmful algal blooms that can lead to fish kills and shellfish poisoning?

Accepted Answer

Dinoflagellates (Alveolates)

Protists: Diversity, Classification, and Evolutionary Relationships

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