,BIOL 271 Module 1 Exam | Microbiology
w/Lab Q&A | Portage Learning
1. Microbiology is defined as the study of biological processes at which level?
A) Microscopic level
B) Macroscopic level
C) Chemical level
D) Organ system level
Correct Answer: A) Microscopic level
Rationale: Microbiology investigates organisms and processes too small to be
seen with the naked eye, including bacteria, archaea, fungi, protozoa, and
viruses. It encompasses cellular and molecular events at the microscopic scale.
2. Which of the following is NOT considered a living microorganism?
A) Bacteria
B) Viruses
C) Archaea
D) Protozoa
Correct Answer: B) Viruses
Rationale: Viruses lack cellular structure, metabolism, and independent
replication; they are acellular and require a host cell for propagation, thus not
classified as living microorganisms.
,3. The three domains of life include Bacteria, Archaea, and:
A) Protista
B) Fungi
C) Eukarya
D) Animalia
Correct Answer: C) Eukarya
Rationale: The 1990 three‑domain system groups all life into Bacteria, Archaea,
and Eukarya, based on ribosomal RNA sequences. Eukarya includes all
organisms with nucleated cells.
4. Prokaryotic cells are characterized by the absence of a:
A) Cell wall
B) Plasma membrane
C) Ribosome
D) Nucleus
Correct Answer: D) Nucleus
Rationale: Prokaryotes lack a membrane‑enclosed nucleus; their genetic
material is located in a nucleoid region. They have a plasma membrane,
ribosomes, and often a cell wall.
5. Eukaryotic cells differ from prokaryotic cells in that they possess:
, A) A cell wall
B) A defined nucleus
C) Circular DNA
D) 70S ribosomes
Correct Answer: B) A defined nucleus
Rationale: Eukaryotic cells contain a true nucleus enclosed by a nuclear
envelope, separating DNA from the cytoplasm. Prokaryotes lack this
compartmentalization and have a nucleoid.
6. Archaea are often referred to as extremophiles because they can:
A) Cause disease
B) Form spores
C) Survive in extreme environments
D) Photosynthesize
Correct Answer: C) Survive in extreme environments
Rationale: Many archaea thrive in high temperature, high salinity, acidic, or
anaerobic conditions that would kill most other organisms. They are adapted to
harsh ecological niches.
7. A bacterium with a spherical shape is termed:
A) Bacillus
B) Vibrio
w/Lab Q&A | Portage Learning
1. Microbiology is defined as the study of biological processes at which level?
A) Microscopic level
B) Macroscopic level
C) Chemical level
D) Organ system level
Correct Answer: A) Microscopic level
Rationale: Microbiology investigates organisms and processes too small to be
seen with the naked eye, including bacteria, archaea, fungi, protozoa, and
viruses. It encompasses cellular and molecular events at the microscopic scale.
2. Which of the following is NOT considered a living microorganism?
A) Bacteria
B) Viruses
C) Archaea
D) Protozoa
Correct Answer: B) Viruses
Rationale: Viruses lack cellular structure, metabolism, and independent
replication; they are acellular and require a host cell for propagation, thus not
classified as living microorganisms.
,3. The three domains of life include Bacteria, Archaea, and:
A) Protista
B) Fungi
C) Eukarya
D) Animalia
Correct Answer: C) Eukarya
Rationale: The 1990 three‑domain system groups all life into Bacteria, Archaea,
and Eukarya, based on ribosomal RNA sequences. Eukarya includes all
organisms with nucleated cells.
4. Prokaryotic cells are characterized by the absence of a:
A) Cell wall
B) Plasma membrane
C) Ribosome
D) Nucleus
Correct Answer: D) Nucleus
Rationale: Prokaryotes lack a membrane‑enclosed nucleus; their genetic
material is located in a nucleoid region. They have a plasma membrane,
ribosomes, and often a cell wall.
5. Eukaryotic cells differ from prokaryotic cells in that they possess:
, A) A cell wall
B) A defined nucleus
C) Circular DNA
D) 70S ribosomes
Correct Answer: B) A defined nucleus
Rationale: Eukaryotic cells contain a true nucleus enclosed by a nuclear
envelope, separating DNA from the cytoplasm. Prokaryotes lack this
compartmentalization and have a nucleoid.
6. Archaea are often referred to as extremophiles because they can:
A) Cause disease
B) Form spores
C) Survive in extreme environments
D) Photosynthesize
Correct Answer: C) Survive in extreme environments
Rationale: Many archaea thrive in high temperature, high salinity, acidic, or
anaerobic conditions that would kill most other organisms. They are adapted to
harsh ecological niches.
7. A bacterium with a spherical shape is termed:
A) Bacillus
B) Vibrio
