Question 1

Which of the following best explains why the kingdom 'Protista' is no longer considered valid by scientists?

Accepted Answer

Protists are polyphyletic, meaning they do not share a single common ancestor.

Question 2

Which of the following is a defining characteristic of the Excavata group of protists?

Accepted Answer

Reduced mitochondria and a crystalline rod in their flagella.

Question 3

Diplomonads, a subgroup of Excavata, are best described as:

Accepted Answer

Protists with reduced mitochondria and two equal-sized nuclei.

Question 4

Which SAR subgroup includes diatoms, brown algae, and oomycetes?

Accepted Answer

Stramenopiles

Question 5

Why is brown algae not considered a plant, despite its photosynthetic ability?

Accepted Answer

Brown algae do not have true roots, stems, or leaves.

Question 6

Alternation of generations in brown algae involves which of the following?

Accepted Answer

A life cycle alternating between multicellular haploid and diploid stages.

Question 7

Which SAR subgroup includes organisms responsible for malaria?

Accepted Answer

Alveolates

Question 8

The two-host life cycle of Plasmodium (malaria parasite) involves which hosts?

Accepted Answer

Human and mosquito

Question 9

Which of the following best describes the function of the flagella in Euglenozoans?

Accepted Answer

Flagella are used for movement and contain a crystalline rod.

Question 10

Which group of protists is most closely related to land plants?

Accepted Answer

Green algae

Question 11

Which of the following is a key difference between the two major subdivisions of unikonts: amoebozoans and opisthokonts?

Accepted Answer

Amoebozoans move using pseudopodia, while opisthokonts include animals and fungi.

Question 12

Which formula best represents the alternation of generations in brown algae?

Accepted Answer

$$2n \rightarrow n \rightarrow 2n$$

Question 13

Which of the following is NOT a characteristic of diatoms?

Accepted Answer

Crystalline rod in flagella

Question 14

Which process allows green algae to transition from unicellular to multicellular forms?

Accepted Answer

Cellular aggregation and specialization

Question 15

Which of the following best describes the relationship between green algae and land plants?

Accepted Answer

Green algae are the direct ancestors of land plants.

Question 16

Which of the following is a real-world consequence of diatom blooms in aquatic environments?

Accepted Answer

Increase in oxygen production and potential for algal toxins.

Question 17

Which formula represents the process of photosynthesis in protists such as green algae?

Accepted Answer

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 18

Which of the following is a plausible reason why multicellularity evolved in green algae?

Accepted Answer

To increase surface area for photosynthesis and allow for cellular specialization.

Question 19

Which of the following best describes the structure of a euglenid?

Accepted Answer

Unicellular organism with a crystalline rod in its flagella and capable of photosynthesis.

Question 20

Which of the following is a key feature distinguishing alveolates from other SAR protists?

Accepted Answer

Presence of membrane-bound sacs (alveoli) under the plasma membrane.

Overview and Classification of Protists

Study Guide - Practice Questions