McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1: Cellular Biology
1. Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a membrane-
bound receptor, activating a G-protein which then stimulates
the enzyme adenylate cyclase. This enzyme's primary action in
the signal transduction pathway is to:
A. Phosphorylate tyrosine residues on the receptor itself.
B. Convert adenosine triphosphate (ATP) to cyclic adenosine
monophosphate (cAMP).
C. Cleave membrane phospholipids to form inositol
triphosphate (IP3) and diacylglycerol (DAG).
D. Directly open ion channels to alter the cell's membrane
potential.
Correct Answer: B
Rationale: B is correct. Adenylate cyclase is the key enzyme in
the cAMP second messenger system; it catalyzes the conversion
of ATP to cAMP. A is incorrect as this describes the action of
receptor enzymes like tyrosine kinases. C is incorrect as this is
the function of phospholipase C, which is activated by a
different type of G-protein. D is incorrect; while some receptors
,are ligand-gated ion channels, adenylate cyclase is not involved
in this direct mechanism.
Teaching Point: cAMP is a critical second messenger generated
by adenylate cyclase in response to first-messenger binding.
2. Chapter 1, Structure and Function of Cellular Components
A patient with a rare genetic disorder presents with severe
recurrent infections and neutropenia. Genetic testing reveals a
mutation impairing the function of lysosomal proteins. Which of
the following cellular processes is most directly compromised
by this defect?
A. Oxidative phosphorylation
B. Detoxification of free radicals
C. Intracellular digestion of phagocytosed material
D. Synthesis of secretory proteins
Correct Answer: C
Rationale: C is correct. Lysosomes are membrane-bound
organelles containing hydrolytic enzymes responsible for
breaking down and digesting cellular waste, including
pathogens engulfed by phagocytes. A is incorrect as this is the
primary function of mitochondria. B is incorrect; this is primarily
the role of peroxisomes. D is incorrect; this is the function of
the rough endoplasmic reticulum and Golgi apparatus.
Teaching Point: Lysosomes are the digestive system of the cell,
crucial for degrading intracellular debris and pathogens.
3. Chapter 1, Membrane Transport: Cellular Intake and Output
Glucose is transported from the intestinal lumen into the
,epithelial cell against its concentration gradient by coupling its
transport with the simultaneous transport of sodium ions down
their gradient. This process is best described as:
A. Simple diffusion
B. Facilitated diffusion
C. Primary active transport
D. Secondary active transport
Correct Answer: D
Rationale: D is correct. Secondary active transport uses the
energy stored in an electrochemical gradient (in this case, for
sodium) established by primary active transport (the Na+/K+
ATPase pump) to move another molecule (glucose) against its
gradient. A is incorrect as simple diffusion requires no
transporter and moves down a gradient. B is incorrect as
facilitated diffusion uses a carrier but moves a solute down its
gradient without energy coupling. C is incorrect as primary
active transport directly uses ATP (e.g., the Na+/K+ ATPase
pump itself).
Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
molecule.
4. Chapter 1, Cellular Reproduction: The Cell Cycle
A chemotherapeutic agent is designed to target and inhibit the
enzyme topoisomerase. During which specific phase of the cell
cycle would this drug be most effective at halting cell division?
A. G0
, B. G1
C. S
D. M
Correct Answer: C
Rationale: C is correct. Topoisomerase is a key enzyme involved
in DNA replication during the S (synthesis) phase. It relieves
torsional stress ahead of the replication fork by creating and
resealing breaks in the DNA backbone. A is incorrect; G0 is a
quiescent phase where cells are not actively dividing. B is
incorrect; G1 is a growth and preparation phase before DNA
replication. D is incorrect; the M phase is mitosis, where DNA
has already been replicated.
Teaching Point: Topoisomerase inhibitors disrupt DNA
replication in the S phase, preventing cancer cell proliferation.
5. Chapter 1, Cellular Communication and Signal Transduction
A student is reviewing the actions of different chemical
messengers. Which of the following messengers must bind to
an intracellular receptor to exert its effects on gene
transcription?
A. Acetylcholine
B. Insulin
C. Thyroxine (T4)
D. Epinephrine
Correct Answer: C
Rationale: C is correct. Thyroid hormones and steroid
hormones are lipid-soluble and can diffuse directly through the
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1: Cellular Biology
1. Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a membrane-
bound receptor, activating a G-protein which then stimulates
the enzyme adenylate cyclase. This enzyme's primary action in
the signal transduction pathway is to:
A. Phosphorylate tyrosine residues on the receptor itself.
B. Convert adenosine triphosphate (ATP) to cyclic adenosine
monophosphate (cAMP).
C. Cleave membrane phospholipids to form inositol
triphosphate (IP3) and diacylglycerol (DAG).
D. Directly open ion channels to alter the cell's membrane
potential.
Correct Answer: B
Rationale: B is correct. Adenylate cyclase is the key enzyme in
the cAMP second messenger system; it catalyzes the conversion
of ATP to cAMP. A is incorrect as this describes the action of
receptor enzymes like tyrosine kinases. C is incorrect as this is
the function of phospholipase C, which is activated by a
different type of G-protein. D is incorrect; while some receptors
,are ligand-gated ion channels, adenylate cyclase is not involved
in this direct mechanism.
Teaching Point: cAMP is a critical second messenger generated
by adenylate cyclase in response to first-messenger binding.
2. Chapter 1, Structure and Function of Cellular Components
A patient with a rare genetic disorder presents with severe
recurrent infections and neutropenia. Genetic testing reveals a
mutation impairing the function of lysosomal proteins. Which of
the following cellular processes is most directly compromised
by this defect?
A. Oxidative phosphorylation
B. Detoxification of free radicals
C. Intracellular digestion of phagocytosed material
D. Synthesis of secretory proteins
Correct Answer: C
Rationale: C is correct. Lysosomes are membrane-bound
organelles containing hydrolytic enzymes responsible for
breaking down and digesting cellular waste, including
pathogens engulfed by phagocytes. A is incorrect as this is the
primary function of mitochondria. B is incorrect; this is primarily
the role of peroxisomes. D is incorrect; this is the function of
the rough endoplasmic reticulum and Golgi apparatus.
Teaching Point: Lysosomes are the digestive system of the cell,
crucial for degrading intracellular debris and pathogens.
3. Chapter 1, Membrane Transport: Cellular Intake and Output
Glucose is transported from the intestinal lumen into the
,epithelial cell against its concentration gradient by coupling its
transport with the simultaneous transport of sodium ions down
their gradient. This process is best described as:
A. Simple diffusion
B. Facilitated diffusion
C. Primary active transport
D. Secondary active transport
Correct Answer: D
Rationale: D is correct. Secondary active transport uses the
energy stored in an electrochemical gradient (in this case, for
sodium) established by primary active transport (the Na+/K+
ATPase pump) to move another molecule (glucose) against its
gradient. A is incorrect as simple diffusion requires no
transporter and moves down a gradient. B is incorrect as
facilitated diffusion uses a carrier but moves a solute down its
gradient without energy coupling. C is incorrect as primary
active transport directly uses ATP (e.g., the Na+/K+ ATPase
pump itself).
Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
molecule.
4. Chapter 1, Cellular Reproduction: The Cell Cycle
A chemotherapeutic agent is designed to target and inhibit the
enzyme topoisomerase. During which specific phase of the cell
cycle would this drug be most effective at halting cell division?
A. G0
, B. G1
C. S
D. M
Correct Answer: C
Rationale: C is correct. Topoisomerase is a key enzyme involved
in DNA replication during the S (synthesis) phase. It relieves
torsional stress ahead of the replication fork by creating and
resealing breaks in the DNA backbone. A is incorrect; G0 is a
quiescent phase where cells are not actively dividing. B is
incorrect; G1 is a growth and preparation phase before DNA
replication. D is incorrect; the M phase is mitosis, where DNA
has already been replicated.
Teaching Point: Topoisomerase inhibitors disrupt DNA
replication in the S phase, preventing cancer cell proliferation.
5. Chapter 1, Cellular Communication and Signal Transduction
A student is reviewing the actions of different chemical
messengers. Which of the following messengers must bind to
an intracellular receptor to exert its effects on gene
transcription?
A. Acetylcholine
B. Insulin
C. Thyroxine (T4)
D. Epinephrine
Correct Answer: C
Rationale: C is correct. Thyroid hormones and steroid
hormones are lipid-soluble and can diffuse directly through the
