McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
McCance & Huether — Pathophysiology, 9th Ed. — Chapter 1:
Cellular Biology.
Chapter 1: Cellular Biology
1. Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a
transmembrane receptor, activating a G-protein which then
stimulates the enzyme adenylate cyclase. This enzyme is
responsible for producing a key second messenger. What is the
primary second messenger generated by this pathway?
A. Inositol trisphosphate (IP3)
B. Diacylglycerol (DAG)
C. Calcium (Ca²⁺)
D. Cyclic adenosine monophosphate (cAMP)
,Correct Answer: D
Rationale: D is correct. The pathway described is a classic G-
protein-coupled receptor (GPCR) pathway. Activation of
adenylate cyclase catalyzes the conversion of ATP to cyclic AMP
(cAMP), a ubiquitous second messenger that activates protein
kinase A. A and B are incorrect because IP3 and DAG are second
messengers generated by the phospholipase C (PLC) pathway,
not the adenylate cyclase pathway. C is incorrect; while calcium
can act as a second messenger, its release is often triggered by
IP3, not directly by adenylate cyclase.
Teaching Point: cAMP is the key second messenger in the GPCR-
adenylate cyclase signal transduction pathway.
2. Chapter 1, Structure and Function of Cellular Components
A patient with a rare genetic disorder presents with severe
fatigue and muscle weakness. A muscle biopsy reveals cells with
markedly abnormal, large mitochondria with disrupted cristae.
Which cellular process is most directly impaired by this
ultrastructural defect?
A. Lipid synthesis
B. Protein synthesis
C. ATP production
D. DNA replication
Correct Answer: C
Rationale: C is correct. Mitochondria are the organelles
responsible for aerobic ATP production via oxidative
,phosphorylation, which occurs on the cristae membranes.
Disruption of the cristae directly impairs the electron transport
chain. A is primarily a function of the smooth endoplasmic
reticulum. B is a function of ribosomes and the rough
endoplasmic reticulum. D occurs in the nucleus.
Teaching Point: The mitochondrial cristae house the electron
transport chain, which is essential for efficient ATP production.
3. Chapter 1, Membrane Transport: Cellular Intake and Output
In the nephron, glucose is reabsorbed from the filtrate back into
the bloodstream against its concentration gradient. This process
is coupled to the movement of sodium down its concentration
gradient and does not directly require ATP at the point of
transport. Which transport mechanism is described?
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 ion gradient (in this case, sodium) to move
another substance (glucose) against its gradient. The sodium
gradient itself is maintained by primary active transport (the
Na⁺/K⁺ ATPase pump). A is incorrect as it describes movement
down a gradient without a carrier. B is incorrect as it describes
passive carrier-mediated transport down a gradient. C is
, incorrect because primary active transport directly uses ATP
(e.g., the Na⁺/K⁺ ATPase pump).
Teaching Point: Secondary active transport harnesses an ion
gradient, established by primary active transport, to move
another molecule.
4. Chapter 1, Cellular Communication and Signal Transduction
A laboratory develops a drug that is a small, nonpolar molecule
capable of diffusing directly through the plasma membrane of a
cell. Upon entering the cell, this drug is most likely to bind to
which type of receptor?
A. A transmembrane G-protein-coupled receptor
B. A transmembrane ligand-gated ion channel
C. An intracellular receptor
D. A transmembrane enzyme-linked receptor
Correct Answer: C
Rationale: C is correct. Intracellular receptors, such as those for
steroid hormones (e.g., cortisol, estrogen), are located within
the cell (cytosol or nucleus) because their ligands are small,
hydrophobic molecules that can diffuse through the lipid
bilayer. A, B, and D are all types of transmembrane receptors
that bind ligands (which are typically water-soluble) on the cell's
exterior surface.
Teaching Point: Lipophilic signaling molecules diffuse through
the membrane to bind intracellular receptors.
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
McCance & Huether — Pathophysiology, 9th Ed. — Chapter 1:
Cellular Biology.
Chapter 1: Cellular Biology
1. Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a
transmembrane receptor, activating a G-protein which then
stimulates the enzyme adenylate cyclase. This enzyme is
responsible for producing a key second messenger. What is the
primary second messenger generated by this pathway?
A. Inositol trisphosphate (IP3)
B. Diacylglycerol (DAG)
C. Calcium (Ca²⁺)
D. Cyclic adenosine monophosphate (cAMP)
,Correct Answer: D
Rationale: D is correct. The pathway described is a classic G-
protein-coupled receptor (GPCR) pathway. Activation of
adenylate cyclase catalyzes the conversion of ATP to cyclic AMP
(cAMP), a ubiquitous second messenger that activates protein
kinase A. A and B are incorrect because IP3 and DAG are second
messengers generated by the phospholipase C (PLC) pathway,
not the adenylate cyclase pathway. C is incorrect; while calcium
can act as a second messenger, its release is often triggered by
IP3, not directly by adenylate cyclase.
Teaching Point: cAMP is the key second messenger in the GPCR-
adenylate cyclase signal transduction pathway.
2. Chapter 1, Structure and Function of Cellular Components
A patient with a rare genetic disorder presents with severe
fatigue and muscle weakness. A muscle biopsy reveals cells with
markedly abnormal, large mitochondria with disrupted cristae.
Which cellular process is most directly impaired by this
ultrastructural defect?
A. Lipid synthesis
B. Protein synthesis
C. ATP production
D. DNA replication
Correct Answer: C
Rationale: C is correct. Mitochondria are the organelles
responsible for aerobic ATP production via oxidative
,phosphorylation, which occurs on the cristae membranes.
Disruption of the cristae directly impairs the electron transport
chain. A is primarily a function of the smooth endoplasmic
reticulum. B is a function of ribosomes and the rough
endoplasmic reticulum. D occurs in the nucleus.
Teaching Point: The mitochondrial cristae house the electron
transport chain, which is essential for efficient ATP production.
3. Chapter 1, Membrane Transport: Cellular Intake and Output
In the nephron, glucose is reabsorbed from the filtrate back into
the bloodstream against its concentration gradient. This process
is coupled to the movement of sodium down its concentration
gradient and does not directly require ATP at the point of
transport. Which transport mechanism is described?
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 ion gradient (in this case, sodium) to move
another substance (glucose) against its gradient. The sodium
gradient itself is maintained by primary active transport (the
Na⁺/K⁺ ATPase pump). A is incorrect as it describes movement
down a gradient without a carrier. B is incorrect as it describes
passive carrier-mediated transport down a gradient. C is
, incorrect because primary active transport directly uses ATP
(e.g., the Na⁺/K⁺ ATPase pump).
Teaching Point: Secondary active transport harnesses an ion
gradient, established by primary active transport, to move
another molecule.
4. Chapter 1, Cellular Communication and Signal Transduction
A laboratory develops a drug that is a small, nonpolar molecule
capable of diffusing directly through the plasma membrane of a
cell. Upon entering the cell, this drug is most likely to bind to
which type of receptor?
A. A transmembrane G-protein-coupled receptor
B. A transmembrane ligand-gated ion channel
C. An intracellular receptor
D. A transmembrane enzyme-linked receptor
Correct Answer: C
Rationale: C is correct. Intracellular receptors, such as those for
steroid hormones (e.g., cortisol, estrogen), are located within
the cell (cytosol or nucleus) because their ligands are small,
hydrophobic molecules that can diffuse through the lipid
bilayer. A, B, and D are all types of transmembrane receptors
that bind ligands (which are typically water-soluble) on the cell's
exterior surface.
Teaching Point: Lipophilic signaling molecules diffuse through
the membrane to bind intracellular receptors.
