Q: Lynn Margulis proposed the endosymbiosis theory to explain the origin of mitochondria. According to this theory, which equation best represents the evolutionary event?

$$\text{Eukaryotic cell} + \text{Proteobacterium} \rightarrow \text{Cell with mitochondria}$$

Question 1

Which of the following is a shared derived trait (synapomorphy) that defines the Domain Eukarya, distinguishing it from Bacteria and Archaea?

Accepted Answer

Nuclear envelope surrounding the genetic material

Question 2

Lynn Margulis proposed the endosymbiosis theory to explain the origin of mitochondria. According to this theory, which equation best represents the evolutionary event?

Accepted Answer

$$	ext{Eukaryotic cell} + 	ext{Proteobacterium} ightarrow 	ext{Cell with mitochondria}$$

Question 3

Which of the following best explains why multicellularity is considered an analogous trait in eukaryotes?

Accepted Answer

It evolved independently in multiple eukaryotic lineages.

Question 4

A harmful algal bloom is most likely caused by which group of protists, and what is a major ecological impact?

Accepted Answer

Dinoflagellates; fish kills due to toxin release

Question 5

Which of the following statements about the flagellum in eukaryotes is correct?

Accepted Answer

Eukaryotic flagella are composed of microtubules arranged in a 9+2 pattern.

Question 6

Which lineage in the Domain Eukarya lacks mitochondria, and what evolutionary process explains this?

Accepted Answer

Excavata; secondary loss of mitochondria

Question 7

Which of the following best describes the role of protists in aquatic food chains?

Accepted Answer

Protists can function as primary producers, consumers, and decomposers.

Question 8

Which hypothesis explains the evolutionary advantage of having a nuclear envelope in eukaryotes?

Accepted Answer

It separates transcription from translation, allowing for more complex gene regulation.

Question 9

A scientist observes a protist with cilia and a complex internal structure. Which lineage is this organism most likely to belong to?

Accepted Answer

Alveolata

Question 10

Which of the following is NOT a reason why biologists study protists?

Accepted Answer

Protists are the only organisms capable of photosynthesis.

Question 11

Which process is responsible for the origin of chloroplasts in eukaryotes, according to the endosymbiosis theory?

Accepted Answer

Primary endosymbiosis with a cyanobacterium

Question 12

Which of the following best describes the difference between sexual and asexual reproduction in protists?

Accepted Answer

Sexual reproduction increases genetic diversity, while asexual reproduction produces genetically identical offspring.

Question 13

Which of the following is a correct statement about the phylogenetic tree of Eukarya?

Accepted Answer

Each major lineage has at least one distinctive morphological characteristic.

Question 14

Which of the following protists is responsible for causing malaria in humans?

Accepted Answer

Plasmodium

Question 15

Which term describes the movement of protists using temporary extensions of the cell membrane and cytoplasm?

Accepted Answer

Amoeboid movement

Question 16

Which of the following is a major ecological impact of diatoms in aquatic environments?

Accepted Answer

They are major producers of oxygen through photosynthesis.

Question 17

Which of the following best explains why the term 'protist' is no longer used as a formal taxonomic group?

Accepted Answer

Protists are a paraphyletic group, not a monophyletic lineage.

Question 18

A researcher is using transmission electron microscopy (TEM) to study protists. What is the main advantage of this technique?

Accepted Answer

It provides detailed images of internal cell structures at high resolution.

Question 19

Which of the following best describes the process of secondary endosymbiosis in protists?

Accepted Answer

A eukaryotic cell engulfs another eukaryotic cell that already contains a chloroplast.

Diversity of Eukaryotes: Protists and the Domain Eukarya

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