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PORTAGE LEARNING BIOL 271 MICROBIOLOGY EXAM STUDY
GUIDE QUESTIONS EXAM LATEST VERSION QUESTIONS AND
ANSWERS 2026 EDITION
Portage Learning BIOL 271 Microbiology Exam Study Guide
250 Practice Questions with Verified Answers and Rationales
INTRODUCTION: UNDERSTANDING THE BIOL 271 EXAM
BIOL 271 Microbiology at Portage Learning covers the foundational principles of
microbiology, including microbial cell structure and function, growth and metabolism,
genetics, antimicrobial control, and host-pathogen interactions . The exam is typically
administered through LockDown Browser and covers Modules 1-6 .
SECTION 1: MICROBIAL CLASSIFICATION AND TAXONOMY (Questions 1-30)
1. Which of the following correctly lists the taxonomic hierarchy from most
inclusive to most specific?
A. Kingdom, Phylum, Class, Order, Family, Genus, Species
B. Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
C. Domain, Phylum, Kingdom, Class, Order, Family, Genus, Species
D. Species, Genus, Family, Order, Class, Phylum, Kingdom, Domain
Answer: B. Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Rationale: The correct taxonomic hierarchy from most inclusive to most specific is
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species . A helpful
mnemonic is "Dear King Phillip Came Over For Good Soup."
2. A microbiology student observes a microorganism that lacks a true nucleus and
membrane-bound organelles. Under which domain should this organism be
classified?
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A. Eukarya
B. Bacteria or Archaea
C. Protista
D. Fungi
Answer: B. Bacteria or Archaea
Rationale: Organisms lacking a true nucleus and membrane-bound organelles are
prokaryotes. The two prokaryotic domains are Bacteria and Archaea . Eukarya contains
all eukaryotes with a true nucleus. Protista and Fungi are kingdoms within Eukarya .
3. Which domain contains organisms with peptidoglycan in their cell walls?
A. Archaea
B. Eukarya
C. Bacteria
D. Viruses
Answer: C. Bacteria
Rationale: Only Bacteria have peptidoglycan in their cell walls . Archaea have
pseudomurein, and Eukarya have cellulose or chitin. Viruses are not cellular organisms.
4. Archaea differ from Bacteria in that Archaea:
A. Have peptidoglycan
B. Have membrane lipids with ether linkages
C. Have ester-linked membrane lipids
D. Have no cell wall
Answer: B. Have membrane lipids with ether linkages
Rationale: Archaea have ether-linked membrane lipids, while Bacteria have ester-linked
lipids . Archaea also lack peptidoglycan in their cell walls and often inhabit extreme
environments .
5. A bacterial species name is correctly written as:
A. escherichia coli
B. Escherichia Coli
C. Escherichia coli
D. ESCHERICHIA COLI
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Answer: C. Escherichia coli
Rationale: Scientific names follow binomial nomenclature: Genus capitalized + species
lowercase, both italicized or underlined when handwritten . Example: Staphylococcus
aureus or S. aureus after first use.
6. Who is credited with first observing microorganisms using a simple microscope?
A. Robert Hooke
B. Louis Pasteur
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer: C. Antonie van Leeuwenhoek
Rationale: Leeuwenhoek is considered the "father of microbiology" for first observing
"animalcules" (bacteria) under a simple microscope . Hooke observed cells, Pasteur
disproved spontaneous generation, and Lister introduced antiseptic surgery.
7. Which scientist disproved spontaneous generation using swan-neck flasks?
A. Francesco Redi
B. Louis Pasteur
C. Robert Koch
D. John Snow
Answer: B. Louis Pasteur
Rationale: Pasteur's swan-neck flask experiment demonstrated that microorganisms
come from existing microbes in the air, disproving spontaneous generation . Redi
disproved spontaneous generation of maggots using meat and jars.
8. The Germ Theory of Disease states that:
A. All microbes are harmful
B. Microorganisms cause disease
C. Diseases are caused by bad air (miasma)
D. Spontaneous generation is true
Answer: B. Microorganisms cause disease
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Rationale: The Germ Theory of Disease links specific microorganisms to specific
diseases . It was formulated by Robert Koch, who also developed Koch's postulates for
establishing causation .
9. Which of the following is NOT a domain in the three-domain system?
A. Bacteria
B. Archaea
C. Protista
D. Eukarya
Answer: C. Protista
Rationale: The three-domain system includes Bacteria, Archaea, and Eukarya . Protista
is a kingdom within the Eukarya domain, not a domain itself .
10. All multicellular microorganisms classified as Animalia are:
A. Autotrophic
B. Heterotrophic
C. Photosynthetic
D. Chemoautotrophic
Answer: B. Heterotrophic
Rationale: All multicellular microorganisms classified as Animalia are heterotrophic—
they obtain energy by consuming other organisms . Plantae are autotrophic and convert
light energy into chemical energy .
11. Koch's postulates require that: (Select all that apply)
A. The same pathogen must be present in every case of the disease
B. The pathogen must be isolated and grown in pure culture
C. The pathogen must cause disease in a healthy susceptible host
D. The pathogen must be re-isolated from the experimentally infected host
Answer: D. All of the above
Rationale: All four Koch's postulates must be met to establish causation: (1) same
pathogen in every case, (2) isolate and grow in pure culture, (3) cause disease in healthy
host, and (4) re-isolate from infected host .
PORTAGE LEARNING BIOL 271 MICROBIOLOGY EXAM STUDY
GUIDE QUESTIONS EXAM LATEST VERSION QUESTIONS AND
ANSWERS 2026 EDITION
Portage Learning BIOL 271 Microbiology Exam Study Guide
250 Practice Questions with Verified Answers and Rationales
INTRODUCTION: UNDERSTANDING THE BIOL 271 EXAM
BIOL 271 Microbiology at Portage Learning covers the foundational principles of
microbiology, including microbial cell structure and function, growth and metabolism,
genetics, antimicrobial control, and host-pathogen interactions . The exam is typically
administered through LockDown Browser and covers Modules 1-6 .
SECTION 1: MICROBIAL CLASSIFICATION AND TAXONOMY (Questions 1-30)
1. Which of the following correctly lists the taxonomic hierarchy from most
inclusive to most specific?
A. Kingdom, Phylum, Class, Order, Family, Genus, Species
B. Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
C. Domain, Phylum, Kingdom, Class, Order, Family, Genus, Species
D. Species, Genus, Family, Order, Class, Phylum, Kingdom, Domain
Answer: B. Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Rationale: The correct taxonomic hierarchy from most inclusive to most specific is
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species . A helpful
mnemonic is "Dear King Phillip Came Over For Good Soup."
2. A microbiology student observes a microorganism that lacks a true nucleus and
membrane-bound organelles. Under which domain should this organism be
classified?
, Page 2 of 79
A. Eukarya
B. Bacteria or Archaea
C. Protista
D. Fungi
Answer: B. Bacteria or Archaea
Rationale: Organisms lacking a true nucleus and membrane-bound organelles are
prokaryotes. The two prokaryotic domains are Bacteria and Archaea . Eukarya contains
all eukaryotes with a true nucleus. Protista and Fungi are kingdoms within Eukarya .
3. Which domain contains organisms with peptidoglycan in their cell walls?
A. Archaea
B. Eukarya
C. Bacteria
D. Viruses
Answer: C. Bacteria
Rationale: Only Bacteria have peptidoglycan in their cell walls . Archaea have
pseudomurein, and Eukarya have cellulose or chitin. Viruses are not cellular organisms.
4. Archaea differ from Bacteria in that Archaea:
A. Have peptidoglycan
B. Have membrane lipids with ether linkages
C. Have ester-linked membrane lipids
D. Have no cell wall
Answer: B. Have membrane lipids with ether linkages
Rationale: Archaea have ether-linked membrane lipids, while Bacteria have ester-linked
lipids . Archaea also lack peptidoglycan in their cell walls and often inhabit extreme
environments .
5. A bacterial species name is correctly written as:
A. escherichia coli
B. Escherichia Coli
C. Escherichia coli
D. ESCHERICHIA COLI
, Page 3 of 79
Answer: C. Escherichia coli
Rationale: Scientific names follow binomial nomenclature: Genus capitalized + species
lowercase, both italicized or underlined when handwritten . Example: Staphylococcus
aureus or S. aureus after first use.
6. Who is credited with first observing microorganisms using a simple microscope?
A. Robert Hooke
B. Louis Pasteur
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer: C. Antonie van Leeuwenhoek
Rationale: Leeuwenhoek is considered the "father of microbiology" for first observing
"animalcules" (bacteria) under a simple microscope . Hooke observed cells, Pasteur
disproved spontaneous generation, and Lister introduced antiseptic surgery.
7. Which scientist disproved spontaneous generation using swan-neck flasks?
A. Francesco Redi
B. Louis Pasteur
C. Robert Koch
D. John Snow
Answer: B. Louis Pasteur
Rationale: Pasteur's swan-neck flask experiment demonstrated that microorganisms
come from existing microbes in the air, disproving spontaneous generation . Redi
disproved spontaneous generation of maggots using meat and jars.
8. The Germ Theory of Disease states that:
A. All microbes are harmful
B. Microorganisms cause disease
C. Diseases are caused by bad air (miasma)
D. Spontaneous generation is true
Answer: B. Microorganisms cause disease
, Page 4 of 79
Rationale: The Germ Theory of Disease links specific microorganisms to specific
diseases . It was formulated by Robert Koch, who also developed Koch's postulates for
establishing causation .
9. Which of the following is NOT a domain in the three-domain system?
A. Bacteria
B. Archaea
C. Protista
D. Eukarya
Answer: C. Protista
Rationale: The three-domain system includes Bacteria, Archaea, and Eukarya . Protista
is a kingdom within the Eukarya domain, not a domain itself .
10. All multicellular microorganisms classified as Animalia are:
A. Autotrophic
B. Heterotrophic
C. Photosynthetic
D. Chemoautotrophic
Answer: B. Heterotrophic
Rationale: All multicellular microorganisms classified as Animalia are heterotrophic—
they obtain energy by consuming other organisms . Plantae are autotrophic and convert
light energy into chemical energy .
11. Koch's postulates require that: (Select all that apply)
A. The same pathogen must be present in every case of the disease
B. The pathogen must be isolated and grown in pure culture
C. The pathogen must cause disease in a healthy susceptible host
D. The pathogen must be re-isolated from the experimentally infected host
Answer: D. All of the above
Rationale: All four Koch's postulates must be met to establish causation: (1) same
pathogen in every case, (2) isolate and grow in pure culture, (3) cause disease in healthy
host, and (4) re-isolate from infected host .
