Question 1

Which of the following best describes the endosymbiont theory for the origin of eukaryotes, as illustrated in the first image?

Accepted Answer

Eukaryotes arose when a prokaryotic cell engulfed other prokaryotes, which then became organelles such as mitochondria and plastids.

Question 2

According to the endosymbiont theory, which organelle is believed to have evolved first in eukaryotes?

Accepted Answer

Mitochondria

Question 3

Which of the following is NOT a line of evidence supporting the endosymbiont theory?

Accepted Answer

Mitochondria and plastids are found only in prokaryotes.

Question 4

What is the main difference between colonial and multicellular species?

Accepted Answer

Colonial species consist of independent cells living together, while multicellular species have cells that are interdependent and specialized.

Question 5

Which subgroup of protists is most closely related to animals, based on molecular and morphological evidence?

Accepted Answer

Choanoflagellates

Question 6

Diatoms play a significant role in aquatic food chains because:

Accepted Answer

They are primary producers, forming the base of the food chain.

Question 7

Dinoflagellate population blooms can cause which ecological problem?

Accepted Answer

Red tides, which can produce toxins harmful to marine life and humans.

Question 8

How does Paramecium maintain water balance in a hypotonic environment?

Accepted Answer

By pumping water out through its contractile vacuole.

Question 9

Which mode of nutrition describes an organism that can use both photosynthesis and heterotrophic feeding?

Accepted Answer

Mixotroph

Question 10

A diatom bloom can affect global CO$$_2$$ levels by:

Accepted Answer

Decreasing CO$$_2 in $$the atmosphere by photosynthetic uptake and sinking to the ocean floor.

Question 11

Which of the following equations best represents the photosynthetic process carried out by diatoms?

Accepted Answer

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

Question 12

Which mutualistic relationship involves protists?

Accepted Answer

Termites hosting protists in their gut to help digest cellulose.

Question 13

In the Plasmodium life cycle (second image), which step occurs immediately after the mosquito injects sporozoites into a human?

Accepted Answer

Sporozoites enter the liver cells and undergo asexual reproduction.

Question 14

Which of the following is a unique feature of brown algae?

Accepted Answer

They are multicellular and form kelp forests, providing habitat for sea otters.

Question 15

Which protist is responsible for causing malaria?

Accepted Answer

Plasmodium

Question 16

Which equation best represents the relationship between water balance and osmotic pressure in Paramecium?

Accepted Answer

$$\Pi = iMRT$$

Question 17

Which protist moves by pseudopodia?

Accepted Answer

Amoeba

Question 18

Which of the following is a plausible consequence of a massive diatom bloom in the ocean?

Accepted Answer

Decrease in atmospheric CO$$_2$$ due to photosynthetic uptake and burial of diatoms.

Question 19

Which protist is commonly found in pond water and is characterized by a flagellum and a red eyespot?

Accepted Answer

Euglena

Study Guide: Origin and Diversification of Eukaryotes & Protist Biology

Study Guide - Practice Questions