Nursing Microbiology 2026 Study Guide Practice
Questions: Answer Explanations on Microbial
Diseases, Pathogens, Immunity, Infection Prevention,
and Clinical Nursing Concepts
Section 1: Microbial Classification and Structure (Questions 1–25)
1. A nurse is reviewing the classification of microorganisms. Which type of
microorganism is considered the smallest and simplest?
A. Bacteria
B. Fungi
C. Viruses
D. Protozoa
Rationale: Viruses are the smallest and simplest microorganisms. They consist of
genetic material (DNA or RNA) enclosed in a protein coat and require a host cell
to replicate. Bacteria, fungi, and protozoa are larger and more complex.
2. A nurse is teaching about bacterial structure. Which component is unique
to gram-positive bacteria?
A. Outer membrane
B. Thick peptidoglycan layer
C. Lipopolysaccharide
D. Flagella
Rationale: Gram-positive bacteria have a thick peptidoglycan layer that retains the
crystal violet stain. Gram-negative bacteria have a thin peptidoglycan layer and an
outer membrane containing lipopolysaccharide.
3. Which bacterial structure is responsible for motility?
A. Pili
B. Capsule
C. Flagella
D. Spore
Rationale: Flagella are whip-like appendages that provide motility. Pili are used
for attachment and conjugation, capsules protect against phagocytosis, and spores
are dormant survival structures.
,4. A nurse is reviewing the structure of viruses. Which component is essential
for viral attachment to host cells?
A. Capsid
B. Envelope proteins
C. Nucleic acid
D. Core enzyme
Rationale: Envelope proteins (glycoproteins) mediate attachment to specific host
cell receptors. The capsid protects the nucleic acid, and the nucleic acid contains
genetic information.
5. A nurse is teaching about fungal infections. Which type of fungus is a
single-celled organism that reproduces by budding?
A. Mold
B. Yeast
C. Mushroom
D. Hyphae
Rationale: Yeasts are single-celled fungi that reproduce by budding. Molds are
multicellular and form hyphae. Mushrooms are the fruiting bodies of certain fungi.
6. A nurse is reviewing the classification of parasites. Which organism is a
protozoan?
A. Tapeworm
B. Giardia lamblia
C. Roundworm
D. Fluke
Rationale: Giardia lamblia is a protozoan parasite. Tapeworms, roundworms, and
flukes are helminths (worms).
7. A nurse is teaching about bacterial spores. Which statement is correct?
A. Spores are easily killed by disinfectants.
B. Spores are highly resistant to heat and disinfectants.
C. Spores are reproductive structures.
D. Spores are found in all bacteria.
Rationale: Bacterial spores (endospores) are highly resistant to heat, radiation, and
disinfectants. They are produced by certain genera such as Clostridium and
Bacillus.
,8. A nurse is reviewing the structure of bacteria. Which component is
responsible for attachment to host cells?
A. Flagella
B. Pili (fimbriae)
C. Capsule
D. Cell wall
Rationale: Pili (fimbriae) are hair-like structures that mediate attachment to host
cells. Flagella provide motility, capsules protect against phagocytosis, and the cell
wall provides structural support.
9. A nurse is teaching about viral replication. Which step occurs first in the
viral replication cycle?
A. Penetration
B. Attachment
C. Uncoating
D. Assembly
Rationale: The viral replication cycle begins with attachment to a host cell
receptor, followed by penetration, uncoating, replication, assembly, and release.
10. A nurse is reviewing the classification of bacteria based on oxygen
requirements. Which term describes bacteria that require oxygen to survive?
A. Anaerobic
B. Obligate aerobic
C. Facultative anaerobic
D. Microaerophilic
Rationale: Obligate aerobes require oxygen for growth. Anaerobes grow in the
absence of oxygen. Facultative anaerobes can grow with or without oxygen.
11. A nurse is teaching about the Gram stain. Which color indicates gram-
negative bacteria?
A. Purple
B. Pink/red
C. Blue
D. Green
Rationale: Gram-negative bacteria appear pink/red after the Gram stain because
they do not retain the crystal violet stain. Gram-positive bacteria appear purple.
, 12. A nurse is reviewing the structure of fungi. Which term describes the
thread-like structures of molds?
A. Yeasts
B. Hyphae
C. Spores
D. Capsules
Rationale: Hyphae are the thread-like filaments that make up the body of a mold.
Yeasts are single-celled fungi, spores are reproductive structures, and capsules are
protective layers.
13. A nurse is teaching about prions. Which statement is correct about
prions?
A. They contain DNA.
B. They are infectious proteins.
C. They are easily destroyed by sterilization.
D. They are a type of bacteria.
Rationale: Prions are infectious proteins that lack nucleic acids. They are highly
resistant to standard sterilization methods and cause neurodegenerative diseases.
14. A nurse is reviewing the classification of microorganisms. Which type of
microorganism is a eukaryote?
A. Bacteria
B. Fungi
C. Viruses
D. Prions
Rationale: Fungi are eukaryotes, meaning they have a true nucleus and
membrane-bound organelles. Bacteria are prokaryotes, viruses are acellular, and
prions are infectious proteins.
15. A nurse is teaching about bacterial cell walls. Which component is
targeted by penicillin?
A. Outer membrane
B. Peptidoglycan
C. Lipopolysaccharide
D. Capsule
Rationale: Penicillin inhibits cell wall synthesis by targeting peptidoglycan cross-
linking. This weakens the cell wall and causes bacterial lysis.
Questions: Answer Explanations on Microbial
Diseases, Pathogens, Immunity, Infection Prevention,
and Clinical Nursing Concepts
Section 1: Microbial Classification and Structure (Questions 1–25)
1. A nurse is reviewing the classification of microorganisms. Which type of
microorganism is considered the smallest and simplest?
A. Bacteria
B. Fungi
C. Viruses
D. Protozoa
Rationale: Viruses are the smallest and simplest microorganisms. They consist of
genetic material (DNA or RNA) enclosed in a protein coat and require a host cell
to replicate. Bacteria, fungi, and protozoa are larger and more complex.
2. A nurse is teaching about bacterial structure. Which component is unique
to gram-positive bacteria?
A. Outer membrane
B. Thick peptidoglycan layer
C. Lipopolysaccharide
D. Flagella
Rationale: Gram-positive bacteria have a thick peptidoglycan layer that retains the
crystal violet stain. Gram-negative bacteria have a thin peptidoglycan layer and an
outer membrane containing lipopolysaccharide.
3. Which bacterial structure is responsible for motility?
A. Pili
B. Capsule
C. Flagella
D. Spore
Rationale: Flagella are whip-like appendages that provide motility. Pili are used
for attachment and conjugation, capsules protect against phagocytosis, and spores
are dormant survival structures.
,4. A nurse is reviewing the structure of viruses. Which component is essential
for viral attachment to host cells?
A. Capsid
B. Envelope proteins
C. Nucleic acid
D. Core enzyme
Rationale: Envelope proteins (glycoproteins) mediate attachment to specific host
cell receptors. The capsid protects the nucleic acid, and the nucleic acid contains
genetic information.
5. A nurse is teaching about fungal infections. Which type of fungus is a
single-celled organism that reproduces by budding?
A. Mold
B. Yeast
C. Mushroom
D. Hyphae
Rationale: Yeasts are single-celled fungi that reproduce by budding. Molds are
multicellular and form hyphae. Mushrooms are the fruiting bodies of certain fungi.
6. A nurse is reviewing the classification of parasites. Which organism is a
protozoan?
A. Tapeworm
B. Giardia lamblia
C. Roundworm
D. Fluke
Rationale: Giardia lamblia is a protozoan parasite. Tapeworms, roundworms, and
flukes are helminths (worms).
7. A nurse is teaching about bacterial spores. Which statement is correct?
A. Spores are easily killed by disinfectants.
B. Spores are highly resistant to heat and disinfectants.
C. Spores are reproductive structures.
D. Spores are found in all bacteria.
Rationale: Bacterial spores (endospores) are highly resistant to heat, radiation, and
disinfectants. They are produced by certain genera such as Clostridium and
Bacillus.
,8. A nurse is reviewing the structure of bacteria. Which component is
responsible for attachment to host cells?
A. Flagella
B. Pili (fimbriae)
C. Capsule
D. Cell wall
Rationale: Pili (fimbriae) are hair-like structures that mediate attachment to host
cells. Flagella provide motility, capsules protect against phagocytosis, and the cell
wall provides structural support.
9. A nurse is teaching about viral replication. Which step occurs first in the
viral replication cycle?
A. Penetration
B. Attachment
C. Uncoating
D. Assembly
Rationale: The viral replication cycle begins with attachment to a host cell
receptor, followed by penetration, uncoating, replication, assembly, and release.
10. A nurse is reviewing the classification of bacteria based on oxygen
requirements. Which term describes bacteria that require oxygen to survive?
A. Anaerobic
B. Obligate aerobic
C. Facultative anaerobic
D. Microaerophilic
Rationale: Obligate aerobes require oxygen for growth. Anaerobes grow in the
absence of oxygen. Facultative anaerobes can grow with or without oxygen.
11. A nurse is teaching about the Gram stain. Which color indicates gram-
negative bacteria?
A. Purple
B. Pink/red
C. Blue
D. Green
Rationale: Gram-negative bacteria appear pink/red after the Gram stain because
they do not retain the crystal violet stain. Gram-positive bacteria appear purple.
, 12. A nurse is reviewing the structure of fungi. Which term describes the
thread-like structures of molds?
A. Yeasts
B. Hyphae
C. Spores
D. Capsules
Rationale: Hyphae are the thread-like filaments that make up the body of a mold.
Yeasts are single-celled fungi, spores are reproductive structures, and capsules are
protective layers.
13. A nurse is teaching about prions. Which statement is correct about
prions?
A. They contain DNA.
B. They are infectious proteins.
C. They are easily destroyed by sterilization.
D. They are a type of bacteria.
Rationale: Prions are infectious proteins that lack nucleic acids. They are highly
resistant to standard sterilization methods and cause neurodegenerative diseases.
14. A nurse is reviewing the classification of microorganisms. Which type of
microorganism is a eukaryote?
A. Bacteria
B. Fungi
C. Viruses
D. Prions
Rationale: Fungi are eukaryotes, meaning they have a true nucleus and
membrane-bound organelles. Bacteria are prokaryotes, viruses are acellular, and
prions are infectious proteins.
15. A nurse is teaching about bacterial cell walls. Which component is
targeted by penicillin?
A. Outer membrane
B. Peptidoglycan
C. Lipopolysaccharide
D. Capsule
Rationale: Penicillin inhibits cell wall synthesis by targeting peptidoglycan cross-
linking. This weakens the cell wall and causes bacterial lysis.
