McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a
transmembrane receptor, activating a G-protein. This G-protein
then directly activates an enzyme that produces a potent
secondary messenger. This process is best described as:
A. Signal amplification
B. Ligand-receptor interaction
C. Second-messenger system activation
D. Signal transduction
Correct Answer: D
Rationale for Correct Answer (D): Signal transduction is the
entire process by which an extracellular signal (the hormone) is
converted into an intracellular response through a sequence of
molecular events, including G-protein activation and second-
messenger generation.
Rationale for Incorrect Answers:
A: Signal amplification is a feature of this process (one hormone
molecule activates many second messengers) but is not the
best overall description of the process itself.
,B: Ligand-receptor interaction is only the initial, first step of the
entire signaling cascade.
C: Second-messenger system activation is a key component of
the process but is a subset of the broader signal transduction
pathway.
Teaching Point: Signal transduction describes the multi-step
pathway from first messenger binding to intracellular effector
activation.
Item 2
Chapter 1, Cellular Metabolism
A patient with a genetic disorder presents with severe
hypoglycemia and lactic acidosis after a short fast. Enzyme
studies reveal a deficiency in an enzyme involved in
gluconeogenesis. Which cellular organelle is most directly
compromised in this patient's condition?
A. Lysosome
B. Peroxisome
C. Mitochondria
D. Golgi apparatus
Correct Answer: C
Rationale for Correct Answer (C): Gluconeogenesis, the
synthesis of new glucose, is heavily dependent on
mitochondrial enzymes (e.g., pyruvate carboxylase) to provide
key intermediates and generate ATP.
,Rationale for Incorrect Answers:
A: Lysosomes are involved in cellular waste breakdown, not
energy production.
B: Peroxisomes are involved in fatty acid beta-oxidation and
detoxification, but not primarily in gluconeogenesis.
D: The Golgi apparatus modifies and packages proteins, not
carbohydrates for energy metabolism.
Teaching Point: Mitochondria are essential for aerobic ATP
production and providing intermediates for anabolic pathways
like gluconeogenesis.
Item 3
Chapter 1, Membrane Transport: Cellular Intake and Output
A laboratory experiment demonstrates the movement of
glucose from an area of high concentration in the intestinal
lumen into an epithelial cell against its concentration gradient.
This movement is coupled with the inward flow of sodium ions.
This is an example of:
A. Simple diffusion
B. Primary active transport
C. Facilitated diffusion
D. Secondary active transport
Correct Answer: D
, Rationale for Correct Answer (D): Secondary active transport
uses the energy stored in an electrochemical gradient (in this
case, of sodium ions, established by the Na+/K+ ATPase pump)
to move another molecule (glucose) against its gradient.
Rationale for Incorrect Answers:
A: Simple diffusion involves movement down a concentration
gradient without a carrier protein.
B: Primary active transport (e.g., the Na+/K+ ATPase pump)
directly uses ATP to establish a gradient.
C: Facilitated diffusion uses a carrier protein but moves a
substance down its concentration gradient without energy
expenditure.
Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
molecule.
Item 4
Chapter 1, Structure and Function of Cellular Components
A patient with a chronic respiratory disease has impaired ciliary
function, leading to recurrent infections. The defect is most
likely in which cytoskeletal component?
A. Microfilaments (actin filaments)
B. Intermediate filaments
C. Microtubules
D. Centrosomes
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1, Cellular Communication and Signal Transduction
A researcher is studying a hormone that binds to a
transmembrane receptor, activating a G-protein. This G-protein
then directly activates an enzyme that produces a potent
secondary messenger. This process is best described as:
A. Signal amplification
B. Ligand-receptor interaction
C. Second-messenger system activation
D. Signal transduction
Correct Answer: D
Rationale for Correct Answer (D): Signal transduction is the
entire process by which an extracellular signal (the hormone) is
converted into an intracellular response through a sequence of
molecular events, including G-protein activation and second-
messenger generation.
Rationale for Incorrect Answers:
A: Signal amplification is a feature of this process (one hormone
molecule activates many second messengers) but is not the
best overall description of the process itself.
,B: Ligand-receptor interaction is only the initial, first step of the
entire signaling cascade.
C: Second-messenger system activation is a key component of
the process but is a subset of the broader signal transduction
pathway.
Teaching Point: Signal transduction describes the multi-step
pathway from first messenger binding to intracellular effector
activation.
Item 2
Chapter 1, Cellular Metabolism
A patient with a genetic disorder presents with severe
hypoglycemia and lactic acidosis after a short fast. Enzyme
studies reveal a deficiency in an enzyme involved in
gluconeogenesis. Which cellular organelle is most directly
compromised in this patient's condition?
A. Lysosome
B. Peroxisome
C. Mitochondria
D. Golgi apparatus
Correct Answer: C
Rationale for Correct Answer (C): Gluconeogenesis, the
synthesis of new glucose, is heavily dependent on
mitochondrial enzymes (e.g., pyruvate carboxylase) to provide
key intermediates and generate ATP.
,Rationale for Incorrect Answers:
A: Lysosomes are involved in cellular waste breakdown, not
energy production.
B: Peroxisomes are involved in fatty acid beta-oxidation and
detoxification, but not primarily in gluconeogenesis.
D: The Golgi apparatus modifies and packages proteins, not
carbohydrates for energy metabolism.
Teaching Point: Mitochondria are essential for aerobic ATP
production and providing intermediates for anabolic pathways
like gluconeogenesis.
Item 3
Chapter 1, Membrane Transport: Cellular Intake and Output
A laboratory experiment demonstrates the movement of
glucose from an area of high concentration in the intestinal
lumen into an epithelial cell against its concentration gradient.
This movement is coupled with the inward flow of sodium ions.
This is an example of:
A. Simple diffusion
B. Primary active transport
C. Facilitated diffusion
D. Secondary active transport
Correct Answer: D
, Rationale for Correct Answer (D): Secondary active transport
uses the energy stored in an electrochemical gradient (in this
case, of sodium ions, established by the Na+/K+ ATPase pump)
to move another molecule (glucose) against its gradient.
Rationale for Incorrect Answers:
A: Simple diffusion involves movement down a concentration
gradient without a carrier protein.
B: Primary active transport (e.g., the Na+/K+ ATPase pump)
directly uses ATP to establish a gradient.
C: Facilitated diffusion uses a carrier protein but moves a
substance down its concentration gradient without energy
expenditure.
Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
molecule.
Item 4
Chapter 1, Structure and Function of Cellular Components
A patient with a chronic respiratory disease has impaired ciliary
function, leading to recurrent infections. The defect is most
likely in which cytoskeletal component?
A. Microfilaments (actin filaments)
B. Intermediate filaments
C. Microtubules
D. Centrosomes
