Question 1

Which of the following best distinguishes Archaea from Bacteria?

Accepted Answer

Archaea have unique membrane lipids with ether bonds, while Bacteria have ester-linked lipids.

Question 2

Which method is commonly used to distinguish between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram staining, which differentiates based on cell wall structure

Question 3

Why is nitrogen cycling by bacteria and archaea important for ecosystems?

Accepted Answer

It converts atmospheric nitrogen ($$N_2) $$into forms usable by plants, such as ammonium ($$NH_4$$^+$$) and nitrate (NO_3$^-).$$

Question 4

Which of the following is a benefit of bacteria in human health?

Accepted Answer

They help digest food and synthesize vitamins in the gut.

Question 5

A harmful algal bloom occurs in a coastal region. Which of the following is a likely consequence?

Accepted Answer

Complete shellfish poisoning due to toxins produced by protists.

Question 6

Which equation best represents the process of carbon fixation by cyanobacteria?

Accepted Answer

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

Question 7

Which of the following is a major ecological role of saprobic fungi?

Accepted Answer

Decomposing dead organic matter and recycling nutrients

Question 8

A protist acquires energy by ingesting other organisms. What is this mode of nutrition called?

Accepted Answer

Heterotrophy

Question 9

Which structure is found in fungi and is responsible for nutrient absorption?

Accepted Answer

Mycelium

Question 10

Which of the following best describes the mutualistic relationship between fungi and plant roots known as mycorrhizae?

Accepted Answer

Fungi increase water and nutrient absorption for plants, while plants supply carbohydrates to fungi.

Question 11

Which life cycle stage is unique to Basidiomycetes among fungi?

Accepted Answer

Formation of a dikaryotic mycelium ($$n + n)$$

Question 12

A scientist is studying a protist that alternates between sexual and asexual reproduction. What is this process called?

Accepted Answer

Alternation of generations

Question 13

Which of the following is a major impact of excessive anti-bacterial use on ecosystems?

Accepted Answer

Disruption of microbial communities, leading to reduced nutrient cycling

Question 14

Which of the following is a correct statement about diatoms?

Accepted Answer

They are photosynthetic protists with silica cell walls.

Question 15

Which process do bacteria use to obtain energy from inorganic compounds, such as hydrogen sulfide ($$H_2S$$), in hydrothermal vent communities?

Accepted Answer

Chemolithotrophy

Question 16

A fungal species is observed decomposing lignin and cellulose in a forest. What is the ecological significance of this activity?

Accepted Answer

It recycles carbon and nutrients, supporting the terrestrial carbon cycle.

Question 17

Which of the following best explains why sexual reproduction evolved in protists?

Accepted Answer

It increases genetic diversity, enhancing adaptation to changing environments.

Question 18

Which group of fungi is characterized by the production of zygospores during sexual reproduction?

Accepted Answer

Zygomycetes

Question 19

A protist lineage is responsible for causing shellfish poisoning in humans. Which group does this protist most likely belong to?

Accepted Answer

Dinoflagellates

Question 20

Which of the following is a real-world example of mutualism involving fungi?

Accepted Answer

A lichen, where a fungus and an alga or cyanobacterium live together and benefit each other

Archaea, Bacteria, Protists, and Fungi: Key Concepts and Study Guide

Study Guide - Practice Questions