$$\mathrm{CO}_2 \rightarrow \text{organic molecules} \rightarrow \mathrm{CO}_2$$

Question 1

Which of the following is a distinguishing feature of eukaryotes compared to bacteria and archaea?

Accepted Answer

Presence of a nuclear envelope

Question 2

Protists are considered a paraphyletic group. What does this mean?

Accepted Answer

They do not share a single common ancestor exclusive to all members

Question 3

Which protist caused the Irish potato famine of 1845, and what was its impact?

Accepted Answer

Phytophthora infestans; led to mass starvation and emigration

Question 4

Which equation best represents the process of photosynthesis carried out by autotrophic protists?

Accepted Answer

$$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2$$

Question 5

Why are marine protists considered important in the global carbon cycle?

Accepted Answer

They act as primary producers and contribute to carbon sinks

Question 6

Which of the following best describes the endosymbiosis theory for the origin of mitochondria?

Accepted Answer

A bacterial cell was engulfed by a host cell and became a mitochondrion

Question 7

Which evidence supports the endosymbiosis theory for mitochondria?

Accepted Answer

Mitochondria have their own circular DNA and replicate by fission

Question 8

What is the primary ecological role of diatoms in aquatic environments?

Accepted Answer

Primary producers that fix carbon dioxide

Question 9

Which process allows protists without cell walls to ingest food?

Accepted Answer

Phagocytosis

Question 10

A harmful algal bloom is most likely caused by which group of protists?

Accepted Answer

Dinoflagellates

Question 11

Which of the following is a consequence of secondary endosymbiosis in protists?

Accepted Answer

Chloroplasts surrounded by more than two membranes

Question 12

Which lineage of eukaryotes is characterized by cells with sac-like structures called alveoli under the plasma membrane?

Accepted Answer

Alveolata

Question 13

What is the adaptive advantage of sexual reproduction in protists?

Accepted Answer

Genetically variable offspring may resist rapidly evolving parasites

Question 14

Which equation describes the movement of carbon in the global carbon cycle involving protists?

Accepted Answer

$$\mathrm{CO}_2 ightarrow 	ext{organic molecules} ightarrow \mathrm{CO}_2$$

Question 15

Which structure is hypothesized to have originated from infoldings of the plasma membrane in early eukaryotes?

Accepted Answer

Nuclear envelope

Question 16

Which mode of locomotion is used by protists with long, fingerlike projections called pseudopodia?

Accepted Answer

Amoeboid motion

Question 17

Which group of eukaryotes includes organisms with flagella covered in hollow, hairlike projections?

Accepted Answer

Stramenopila

Question 18

What is the main difference between gametophyte and sporophyte in alternation of generations?

Accepted Answer

Gametophyte is haploid and produces gametes; sporophyte is diploid and produces spores

Question 19

Which protist feeding strategy involves taking up nutrients directly across the plasma membrane?

Accepted Answer

Absorptive feeding

Question 20

Which of the following is a real-world example of protists influencing nutrient cycling?

Accepted Answer

Slime molds feeding on microorganisms in soil

Diversification of Eukaryotes: Protists and Major Eukaryotic Lineages

Study Guide - Practice Questions