Test Bank for Microbiology with Diseases
by Body System (5th Edition) by Robert W.
Bauman – All Chapters 1-26 (Latest Guide)
Which characteristic best distinguishes prokaryotic cells from eukaryotic cells?
A. Prokaryotes contain DNA.
B. Prokaryotes lack a membrane-bound nucleus.
C. Prokaryotes contain ribosomes.
D. Prokaryotes have a plasma membrane.
Answer: B. Prokaryotes lack a membrane-bound nucleus.
Rationale: Prokaryotic cells, including bacteria and archaea, do not have a
membrane-bound nucleus. Their DNA is located in a nucleoid region. Both
prokaryotic and eukaryotic cells contain DNA, ribosomes, and plasma
membranes.
Which bacterial structure is primarily responsible for maintaining the cell's shape
and protecting it from osmotic lysis?
A. Capsule
B. Plasma membrane
C. Cell wall
D. Flagellum
Answer: C. Cell wall.
Rationale: The bacterial cell wall provides structural support and helps prevent
osmotic lysis. In most bacteria, peptidoglycan is the major structural component
of the cell wall.
A bacterium stains purple during a Gram stain. Which structural feature is most
likely responsible for this result?
,A. A thick peptidoglycan layer
B. An outer membrane containing lipopolysaccharide
C. A large capsule
D. A lack of a cell wall
Answer: A. A thick peptidoglycan layer.
Rationale: Gram-positive bacteria have a relatively thick peptidoglycan layer that
retains the crystal violet–iodine complex during the decolorization step, causing
the cells to appear purple.
Which component of Gram-negative bacterial outer membranes contributes to
endotoxin activity?
A. Teichoic acid
B. Lipid A
C. Peptidoglycan
D. Chitin
Answer: B. Lipid A.
Rationale: Lipid A is the biologically active portion of lipopolysaccharide (LPS),
also called endotoxin. Release of substantial amounts of LPS can contribute to
fever, inflammation, hypotension, and septic shock.
What is the primary function of bacterial ribosomes?
A. ATP storage
B. DNA replication
C. Protein synthesis
D. Lipid storage
Answer: C. Protein synthesis.
Rationale: Ribosomes translate messenger RNA into polypeptide chains.
Bacterial ribosomes are 70S structures composed of 30S and 50S subunits.
Which structure allows many bacteria to move through liquid environments?
A. Capsule
B. Flagellum
,C. Fimbria
D. Endospore
Answer: B. Flagellum.
Rationale: Flagella are locomotor structures that allow bacterial movement.
Their rotation can propel bacteria through liquid or across surfaces, depending
on the organism and flagellar arrangement.
Which bacterial structure is most directly associated with attachment to host cells?
A. Fimbriae
B. Endospore
C. Nucleoid
D. Ribosome
Answer: A. Fimbriae.
Rationale: Fimbriae are short, hairlike structures that commonly facilitate
attachment to surfaces and host cells. Adhesion is an important early step in
colonization and infection.
What is the main purpose of bacterial endospore formation?
A. Reproduction
B. Protein synthesis
C. Survival under unfavorable conditions
D. Increased motility
Answer: C. Survival under unfavorable conditions.
Rationale: Endospores are highly resistant structures produced by certain
bacteria, particularly species of Bacillus and Clostridium. They help the
organism survive heat, drying, chemicals, and other environmental stresses.
Which phase of the bacterial growth curve is characterized by rapid cell division?
A. Lag phase
B. Log phase
C. Stationary phase
D. Death phase
, Answer: B. Log phase.
Rationale: During the log or exponential phase, bacteria divide at a relatively
constant and rapid rate. This phase is associated with high metabolic activity and
increasing cell numbers.
Which method is most appropriate for eliminating all microorganisms, including
bacterial endospores, from heat-resistant laboratory equipment?
A. Refrigeration
B. Pasteurization
C. Autoclaving
D. Handwashing
Answer: C. Autoclaving.
Rationale: Autoclaving uses pressurized steam to achieve temperatures sufficient
to destroy vegetative cells and bacterial endospores. It is a standard sterilization
method for suitable heat-resistant materials.
An antibiotic inhibits bacterial cell-wall synthesis. Why can this type of medication
selectively affect bacteria?
A. Human cells contain peptidoglycan.
B. Human cells have bacterial-type cell walls.
C. Human cells lack peptidoglycan cell walls.
D. Human cells contain bacterial endospores.
Answer: C. Human cells lack peptidoglycan cell walls.
Rationale: Peptidoglycan is a bacterial cell-wall component and is absent from
human cells. Drugs targeting peptidoglycan synthesis can therefore exploit a
structural difference between bacteria and humans.
Which process involves the transfer of bacterial DNA through direct contact
between bacterial cells?
A. Transformation
B. Transduction
C. Conjugation
D. Translation
by Body System (5th Edition) by Robert W.
Bauman – All Chapters 1-26 (Latest Guide)
Which characteristic best distinguishes prokaryotic cells from eukaryotic cells?
A. Prokaryotes contain DNA.
B. Prokaryotes lack a membrane-bound nucleus.
C. Prokaryotes contain ribosomes.
D. Prokaryotes have a plasma membrane.
Answer: B. Prokaryotes lack a membrane-bound nucleus.
Rationale: Prokaryotic cells, including bacteria and archaea, do not have a
membrane-bound nucleus. Their DNA is located in a nucleoid region. Both
prokaryotic and eukaryotic cells contain DNA, ribosomes, and plasma
membranes.
Which bacterial structure is primarily responsible for maintaining the cell's shape
and protecting it from osmotic lysis?
A. Capsule
B. Plasma membrane
C. Cell wall
D. Flagellum
Answer: C. Cell wall.
Rationale: The bacterial cell wall provides structural support and helps prevent
osmotic lysis. In most bacteria, peptidoglycan is the major structural component
of the cell wall.
A bacterium stains purple during a Gram stain. Which structural feature is most
likely responsible for this result?
,A. A thick peptidoglycan layer
B. An outer membrane containing lipopolysaccharide
C. A large capsule
D. A lack of a cell wall
Answer: A. A thick peptidoglycan layer.
Rationale: Gram-positive bacteria have a relatively thick peptidoglycan layer that
retains the crystal violet–iodine complex during the decolorization step, causing
the cells to appear purple.
Which component of Gram-negative bacterial outer membranes contributes to
endotoxin activity?
A. Teichoic acid
B. Lipid A
C. Peptidoglycan
D. Chitin
Answer: B. Lipid A.
Rationale: Lipid A is the biologically active portion of lipopolysaccharide (LPS),
also called endotoxin. Release of substantial amounts of LPS can contribute to
fever, inflammation, hypotension, and septic shock.
What is the primary function of bacterial ribosomes?
A. ATP storage
B. DNA replication
C. Protein synthesis
D. Lipid storage
Answer: C. Protein synthesis.
Rationale: Ribosomes translate messenger RNA into polypeptide chains.
Bacterial ribosomes are 70S structures composed of 30S and 50S subunits.
Which structure allows many bacteria to move through liquid environments?
A. Capsule
B. Flagellum
,C. Fimbria
D. Endospore
Answer: B. Flagellum.
Rationale: Flagella are locomotor structures that allow bacterial movement.
Their rotation can propel bacteria through liquid or across surfaces, depending
on the organism and flagellar arrangement.
Which bacterial structure is most directly associated with attachment to host cells?
A. Fimbriae
B. Endospore
C. Nucleoid
D. Ribosome
Answer: A. Fimbriae.
Rationale: Fimbriae are short, hairlike structures that commonly facilitate
attachment to surfaces and host cells. Adhesion is an important early step in
colonization and infection.
What is the main purpose of bacterial endospore formation?
A. Reproduction
B. Protein synthesis
C. Survival under unfavorable conditions
D. Increased motility
Answer: C. Survival under unfavorable conditions.
Rationale: Endospores are highly resistant structures produced by certain
bacteria, particularly species of Bacillus and Clostridium. They help the
organism survive heat, drying, chemicals, and other environmental stresses.
Which phase of the bacterial growth curve is characterized by rapid cell division?
A. Lag phase
B. Log phase
C. Stationary phase
D. Death phase
, Answer: B. Log phase.
Rationale: During the log or exponential phase, bacteria divide at a relatively
constant and rapid rate. This phase is associated with high metabolic activity and
increasing cell numbers.
Which method is most appropriate for eliminating all microorganisms, including
bacterial endospores, from heat-resistant laboratory equipment?
A. Refrigeration
B. Pasteurization
C. Autoclaving
D. Handwashing
Answer: C. Autoclaving.
Rationale: Autoclaving uses pressurized steam to achieve temperatures sufficient
to destroy vegetative cells and bacterial endospores. It is a standard sterilization
method for suitable heat-resistant materials.
An antibiotic inhibits bacterial cell-wall synthesis. Why can this type of medication
selectively affect bacteria?
A. Human cells contain peptidoglycan.
B. Human cells have bacterial-type cell walls.
C. Human cells lack peptidoglycan cell walls.
D. Human cells contain bacterial endospores.
Answer: C. Human cells lack peptidoglycan cell walls.
Rationale: Peptidoglycan is a bacterial cell-wall component and is absent from
human cells. Drugs targeting peptidoglycan synthesis can therefore exploit a
structural difference between bacteria and humans.
Which process involves the transfer of bacterial DNA through direct contact
between bacterial cells?
A. Transformation
B. Transduction
C. Conjugation
D. Translation
