OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
Chapter 1: An Invisible World
* = Correct answer
Multiple Choice
1. Which of the following is true of the microbial world?
A. All microbes are harmful.
B. Humans could survive without microbes.
C. Many microbes are helpful.*
D. Most microbes are pathogenic.
Difficulty: Easy
ASM Standard: 23, 24
2. Which of the following is when humans first suspected the existence of microbes?
A. during the Industrial Revolution
B. in prehistoric times*
C. in the last century
D. within the last 500 years
Difficulty: Easy
ASM Standard: 23
3. Which individual first observed unicellular organisms, which he called “animalcules,” using
a microscope he developed?
A. Robert Koch
B. Louis Pasteur
C. Thucydides
D. Antonie van Leeuwenhoek*
Difficulty: Easy
ASM Standard: 6
4. To reduce the risk of open flame from Bunsen burners, microbiologists are increasingly using
which of the following devices for easy, rapid benchtop sterilization of small pieces of
equipment?
A. autoclaves
B. ethylene oxide
C. incubators
D. microincinerators*
Difficulty: Easy
ASM Standard: 36
Page 1 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
,OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
5. The Swedish botanist known for having developed an important biological classification
system is which of the following people?
A. Ernst Haeckel
B. Carolus Linnaeus*
C. Louis Pasteur
D. Robert Whittaker
Difficulty: Easy
ASM Standard: N/A
6. Which kingdom was the only one found in Empire Prokaryota?
A. Animalia
B. Fungi
C. Monera*
D. Protista
Difficulty: Easy
ASM Standard: N/A
7. Which are the three currently accepted domains?
A. Archaea, Bacteria, and Eukarya*
B. Archaea, Prokaryota, and Eukaryota
C. Bacteria, Fungi, and Protista
D. Bacteria, Prokaryota, and Eukarya
Difficulty: Easy
ASM Standard: N/A
8. Which two taxonomic units are typically used to identify an organism when using binomial
nomenclature?
A. domain and kingdom
B. genus and family
C. genus and species*
D. phylum and class
Difficulty: Easy
ASM Standard: N/A
9. Which of the following is not true about the process of fermentation?
A. It can help preserve foods, preventing spoilage.
B. It converts sugars to organic acids, alcohols, and/or gases such as carbon dioxide.
C. It is carried out exclusively by unicellular eukaryotes such as yeast.*
D. It is used to make foods such as cheese and bread.
Difficulty: Moderate
ASM Standard: 11, 23, 26
Page 2 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
,OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
10. The Romans may have reduced their risk of waterborne infectious diseases by using which of
the following?
A. a variety of pharmaceutical products
B. aqueducts and a sewer system*
C. prophylactic antibiotics
D. quarantine of people with leprosy
Difficulty: Moderate
ASM Standard: 23
11. For which of the following is Thucydides known?
A. developing an effective sewer system in ancient Greece, helping to reduce levels of
disease in cities
B. observing microbes, using a microscope, for the first time, even distinguishing between
bacteria and fungi
C. proposing that disease was caused by microorganisms
D. realizing that people who had been infected by the Athenian plague had immunity to
reinfection*
Difficulty: Moderate
ASM Standard: 23, 31
12. Ernst Haeckel proposed a classification system consisting of which of the following
subgroups?
A. five kingdoms
B. four kingdoms*
C. two domains and three kingdoms
D. two domains and five kingdoms
Difficulty: Moderate
ASM Standard: N/A
13. Viruses not included in phylogenetic trees for which of the following reasons?
A. It is too difficult to observe their characteristics.
B. They are acellular and nonliving.*
C. They do not have any genes, which prevents genetic analysis.
D. They lack a nucleus.
Difficulty: Moderate
ASM Standard: 5
14. Which is the best description of the primary purpose of a phylogeny?
A. Phylogenies show all the alterative names for each species.
B. Phylogenies show all the common names for each species.
C. Phylogenies show evolutionary relatedness between organisms.*
Page 3 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
, OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
D. Phylogenies show interactions between species in a shared habitat.
Difficulty: Moderate
ASM Standard: 5
15. Current phylogenetic analyses include which of the following?
A. information from a range of sources, including morphological, genetic, and biochemical
data*
B. information on visible similarities only
C. information regarding how to classify organisms on the basis of external morphological
characteristics and visible behaviors
D. varied morphological and structural characteristics, with preference for leaving historical
classifications to prevent confusion
Difficulty: Moderate
ASM Standard: 5
16. Diatoms are classified within which of the following domains?
A. Archaea
B. Bacteria
C. Eukarya*
D. Prokaryota
Difficulty: Moderate
ASM Standard: N/A
17. Horizontal gene transfer involves which of the following?
A. any transfer of genes in a laboratory setting
B. the transfer of genes from a virus to a bacterium or vice versa but not any other form of
gene transfer
C. the transfer of genes from one individual to another, including from one species to
another, but not from parent to offspring*
D. the transfer of genes from parent to offspring
Difficulty: Moderate
ASM Standard: 2, 4
18. Bacteria are generally identified to species by using which of the following?
A. a combination of genetic, biochemical, and microscopic approaches*
B. a combination of microscopic and physiological approaches, but not genetics
C. primarily characteristics such as motility that can be visualized using microscopy
D. primarily morphological characteristics of individual cells
Difficulty: Moderate
ASM Standard: 34, 36
Page 4 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
Chapter 1: An Invisible World
* = Correct answer
Multiple Choice
1. Which of the following is true of the microbial world?
A. All microbes are harmful.
B. Humans could survive without microbes.
C. Many microbes are helpful.*
D. Most microbes are pathogenic.
Difficulty: Easy
ASM Standard: 23, 24
2. Which of the following is when humans first suspected the existence of microbes?
A. during the Industrial Revolution
B. in prehistoric times*
C. in the last century
D. within the last 500 years
Difficulty: Easy
ASM Standard: 23
3. Which individual first observed unicellular organisms, which he called “animalcules,” using
a microscope he developed?
A. Robert Koch
B. Louis Pasteur
C. Thucydides
D. Antonie van Leeuwenhoek*
Difficulty: Easy
ASM Standard: 6
4. To reduce the risk of open flame from Bunsen burners, microbiologists are increasingly using
which of the following devices for easy, rapid benchtop sterilization of small pieces of
equipment?
A. autoclaves
B. ethylene oxide
C. incubators
D. microincinerators*
Difficulty: Easy
ASM Standard: 36
Page 1 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
,OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
5. The Swedish botanist known for having developed an important biological classification
system is which of the following people?
A. Ernst Haeckel
B. Carolus Linnaeus*
C. Louis Pasteur
D. Robert Whittaker
Difficulty: Easy
ASM Standard: N/A
6. Which kingdom was the only one found in Empire Prokaryota?
A. Animalia
B. Fungi
C. Monera*
D. Protista
Difficulty: Easy
ASM Standard: N/A
7. Which are the three currently accepted domains?
A. Archaea, Bacteria, and Eukarya*
B. Archaea, Prokaryota, and Eukaryota
C. Bacteria, Fungi, and Protista
D. Bacteria, Prokaryota, and Eukarya
Difficulty: Easy
ASM Standard: N/A
8. Which two taxonomic units are typically used to identify an organism when using binomial
nomenclature?
A. domain and kingdom
B. genus and family
C. genus and species*
D. phylum and class
Difficulty: Easy
ASM Standard: N/A
9. Which of the following is not true about the process of fermentation?
A. It can help preserve foods, preventing spoilage.
B. It converts sugars to organic acids, alcohols, and/or gases such as carbon dioxide.
C. It is carried out exclusively by unicellular eukaryotes such as yeast.*
D. It is used to make foods such as cheese and bread.
Difficulty: Moderate
ASM Standard: 11, 23, 26
Page 2 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
,OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
10. The Romans may have reduced their risk of waterborne infectious diseases by using which of
the following?
A. a variety of pharmaceutical products
B. aqueducts and a sewer system*
C. prophylactic antibiotics
D. quarantine of people with leprosy
Difficulty: Moderate
ASM Standard: 23
11. For which of the following is Thucydides known?
A. developing an effective sewer system in ancient Greece, helping to reduce levels of
disease in cities
B. observing microbes, using a microscope, for the first time, even distinguishing between
bacteria and fungi
C. proposing that disease was caused by microorganisms
D. realizing that people who had been infected by the Athenian plague had immunity to
reinfection*
Difficulty: Moderate
ASM Standard: 23, 31
12. Ernst Haeckel proposed a classification system consisting of which of the following
subgroups?
A. five kingdoms
B. four kingdoms*
C. two domains and three kingdoms
D. two domains and five kingdoms
Difficulty: Moderate
ASM Standard: N/A
13. Viruses not included in phylogenetic trees for which of the following reasons?
A. It is too difficult to observe their characteristics.
B. They are acellular and nonliving.*
C. They do not have any genes, which prevents genetic analysis.
D. They lack a nucleus.
Difficulty: Moderate
ASM Standard: 5
14. Which is the best description of the primary purpose of a phylogeny?
A. Phylogenies show all the alterative names for each species.
B. Phylogenies show all the common names for each species.
C. Phylogenies show evolutionary relatedness between organisms.*
Page 3 of 17
OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf OpenStax Microbiology Test Bank.pdf
, OpenStax Microbiology Test Bank: 2026. 3/31/2026, 11:45:28 AM OpenStax Microbiology Test Bank.pdf
OpenStax Microbiology Test Bank
Chapter 1: An Invisible World
D. Phylogenies show interactions between species in a shared habitat.
Difficulty: Moderate
ASM Standard: 5
15. Current phylogenetic analyses include which of the following?
A. information from a range of sources, including morphological, genetic, and biochemical
data*
B. information on visible similarities only
C. information regarding how to classify organisms on the basis of external morphological
characteristics and visible behaviors
D. varied morphological and structural characteristics, with preference for leaving historical
classifications to prevent confusion
Difficulty: Moderate
ASM Standard: 5
16. Diatoms are classified within which of the following domains?
A. Archaea
B. Bacteria
C. Eukarya*
D. Prokaryota
Difficulty: Moderate
ASM Standard: N/A
17. Horizontal gene transfer involves which of the following?
A. any transfer of genes in a laboratory setting
B. the transfer of genes from a virus to a bacterium or vice versa but not any other form of
gene transfer
C. the transfer of genes from one individual to another, including from one species to
another, but not from parent to offspring*
D. the transfer of genes from parent to offspring
Difficulty: Moderate
ASM Standard: 2, 4
18. Bacteria are generally identified to species by using which of the following?
A. a combination of genetic, biochemical, and microscopic approaches*
B. a combination of microscopic and physiological approaches, but not genetics
C. primarily characteristics such as motility that can be visualized using microscopy
D. primarily morphological characteristics of individual cells
Difficulty: Moderate
ASM Standard: 34, 36
Page 4 of 17
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