Question 1

Which of the following best explains why protists are considered a paraphyletic group?

Accepted Answer

They include some, but not all, descendants of a common ancestor.

Question 2

A scientist discovers a new organism with the following features: a flexible pellicle, chloroplasts with chlorophylls a and b, a contractile vacuole, and an eyespot. Which group does this organism most likely belong to?

Accepted Answer

Euglenoids

Question 3

Which of the following protists is responsible for causing African sleeping sickness?

Accepted Answer

Trypanosoma brucei

Question 4

Which structure in Paramecium is directly involved in sexual reproduction (conjugation)?

Accepted Answer

Micronucleus

Question 5

A patient presents with severe diarrhea after drinking water from a mountain stream. Microscopic examination reveals flagellated cells with two nuclei. Which protist is the most likely cause?

Accepted Answer

Giardia

Question 6

Which of the following best describes the ecological role of diatoms in aquatic environments?

Accepted Answer

They are important components of phytoplankton and primary producers.

Question 7

Which pigment allows red algae to photosynthesize efficiently in deep marine waters?

Accepted Answer

Phycoerythrin

Question 8

A bloom of dinoflagellates in coastal waters can result in which of the following phenomena, and what is a potential consequence for humans?

Accepted Answer

Red tide; shellfish poisoning due to toxins

Question 9

Which of the following statements about the life cycle of Plasmodium (malaria parasite) is correct?

Accepted Answer

Meiosis occurs in the mosquito.

Question 10

Which of the following is a key difference between foraminiferans and radiolarians?

Accepted Answer

Foraminiferans have shells of calcium carbonate, while radiolarians have shells of silica.

Question 11

Which of the following best describes the evolutionary significance of green algae (Chlorophyta and Charophyta)?

Accepted Answer

They are structurally and biochemically most like land plants.

Question 12

Which of the following is a real-world application of brown algae (Phaeophyceae) extracts?

Accepted Answer

Used as a thickening agent in foods such as ice cream and pudding

Question 13

Which of the following features is unique to ciliates among protists?

Accepted Answer

Movement using cilia

Question 14

A protist is observed to be mixotrophic, possessing both chloroplasts and the ability to ingest food particles. Which group is this organism most likely to belong to?

Accepted Answer

Euglenoids

Question 15

Which of the following best describes the function of the contractile vacuole in freshwater protists such as Paramecium and Euglena?

Accepted Answer

It expels excess water to maintain osmotic balance.

Question 16

Which of the following is a distinguishing feature of the alveolates?

Accepted Answer

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

Question 17

Which of the following protists is most likely to be found as a symbiont in coral reefs, contributing to the coral's energy needs?

Accepted Answer

Dinoflagellates

Question 18

Which of the following statements about slime molds is correct?

Accepted Answer

They are heterotrophic and can aggregate to form a migrating mass.

Question 19

Which of the following is a correct match between a protist and the disease it causes?

Accepted Answer

Plasmodium – malaria

Question 20

Which of the following best explains why molecular and biochemical comparisons are important for classifying protists?

Accepted Answer

Protists are highly diverse and not a monophyletic group.

Protists: Diversity, Classification, and Biological Significance

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