Question 1

Which of the following provides the strongest evidence supporting the endosymbiotic origin of mitochondria?

Accepted Answer

Mitochondria contain their own circular DNA and prokaryote-like ribosomes.

Question 2

Which process best describes 'alternation of generations' in protists?

Accepted Answer

Alternating between haploid (N) and diploid (2N) multicellular forms, with meiosis and fertilization occurring in the life cycle.

Question 3

Which of the following is NOT a characteristic that distinguishes protists from prokaryotes?

Accepted Answer

Circular DNA in the cytoplasm.

Question 4

A scientist discovers a unicellular organism with two flagella, crystalline rod structures, and the ability to switch between autotrophic and heterotrophic nutrition. To which group does this organism most likely belong?

Accepted Answer

Euglenids

Question 5

Which of the following best explains why photosynthetic protists are important in aquatic environments?

Accepted Answer

They are the primary producers, forming the base of aquatic food webs and generating oxygen.

Question 6

Which of the following statements about the SAR clade is correct?

Accepted Answer

It includes Stramenopiles, Alveolates, and Rhizarians, with evidence of secondary endosymbiosis.

Question 7

A harmful algal bloom ('red tide') in Florida is most likely caused by which group of protists?

Accepted Answer

Dinoflagellates

Question 8

Which of the following is a key morphological feature of brown algae that is analogous to plant structures?

Accepted Answer

Holdfast, stipe, and blade

Question 9

Which of the following statements about plastids is TRUE according to the endosymbiotic theory?

Accepted Answer

Plastids originated from engulfed cyanobacteria via primary endosymbiosis, and some later acquired additional membranes through secondary endosymbiosis.

Question 10

Which of the following best describes the nutritional diversity found among protists?

Accepted Answer

Protists can be photoautotrophs, heterotrophs, or mixotrophs.

Question 11

A protist that moves using numerous short, hair-like structures and has both a macronucleus and micronucleus is most likely a:

Accepted Answer

Ciliate

Question 12

Which of the following is a direct result of secondary endosymbiosis in protists?

Accepted Answer

The presence of three or four membranes surrounding plastids in some protists.

Question 13

Which group of protists is characterized by the pigment phycoerythrin and is commonly found in shallow tropical waters?

Accepted Answer

Red algae

Question 14

Which of the following is a paraphyletic group that includes both Charophytes and Chlorophytes, and is defined by the presence of chlorophyll a and b?

Accepted Answer

Green algae

Question 15

A patient is diagnosed with sleeping sickness, a disease caused by a protist. Which group does the causative agent belong to, and what is its likely mode of transmission?

Accepted Answer

Kinetoplastids; transmitted by the tsetse fly

Question 16

Which of the following statements about protist reproduction is correct?

Accepted Answer

Protists can reproduce both sexually and asexually, increasing genetic diversity.

Question 17

Which of the following is a key ecological role of protists in symbiotic relationships?

Accepted Answer

They form mutualistic relationships with termites, aiding in cellulose digestion.

Question 18

Which of the following best explains why mitochondria and plastids have double membranes?

Accepted Answer

The double membranes are a result of the engulfing mechanism during endosymbiosis, with the inner membrane derived from the original prokaryote.

Question 19

Which of the following is a reason why protists are not considered a monophyletic group?

Accepted Answer

They do not all share a single common ancestor exclusive to protists.

Question 20

Which of the following best describes the movement of amoeboid protists?

Accepted Answer

They move by sliding via streaming pseudopodia.

Protists: Diversity, Evolution, and Ecological Roles

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