McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1, Section: 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's primary
action in the signal transduction pathway is to:
A. Phosphorylate tyrosine residues on the receptor itself.
B. Convert ATP to the second messenger cyclic AMP (cAMP).
C. Directly open ion channels to alter the cell's electrical
potential.
D. Cleave membrane phospholipids to produce diacylglycerol
(DAG) and inositol trisphosphate (IP3).
Correct Answer: B
Rationale: B is correct because adenylate cyclase is the key
enzyme that catalyzes the conversion of ATP to cyclic AMP
(cAMP), a ubiquitous second messenger. A is incorrect as this
describes the action of receptor tyrosine kinases, not G-protein
coupled receptors. C is incorrect; while some receptors are
ligand-gated ion channels, this is not the function of adenylate
,cyclase. D is incorrect as this is the function of phospholipase C,
which is activated by a different type of G-protein.
Teaching Point: cAMP is a critical second messenger generated
by adenylate cyclase in response to many first messengers.
2.
Chapter 1, Section: Structure and Function of Cellular
Components
A patient with a rare genetic disorder presents with recurrent
infections and neurological deficits. Diagnostic testing reveals
abnormally large inclusions within lysosomes, suggesting an
impairment in the organelle's ability to break down
macromolecules. The most likely defective cellular structure is
the:
A. Golgi apparatus, which is failing to glycosylate proteins
properly.
B. Peroxisome, which is failing to detoxify free radicals.
C. Lysosome, which is missing specific acid hydrolase enzymes.
D. Rough endoplasmic reticulum, which is failing to synthesize
enzymes.
Correct Answer: C
Rationale: C is correct because lysosomes contain acid
hydrolases responsible for breaking down cellular waste and
pathogens. A deficiency in these enzymes leads to the
accumulation of undigested materials, as seen in lysosomal
storage diseases. A, B, and D are incorrect; while these
organelles are involved in processing, detoxification, and
,synthesis respectively, their dysfunction does not primarily
cause the accumulation of undigested material within the
lysosome itself.
Teaching Point: Lysosomal storage diseases result from
deficient acid hydrolases, causing toxic substrate accumulation.
3.
Chapter 1, Section: 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 directly powered by the sodium-potassium pump and is a
classic example of:
A. Primary active transport.
B. Simple diffusion.
C. Secondary active transport (co-transport).
D. Receptor-mediated endocytosis.
Correct Answer: C
Rationale: C is correct because secondary active transport uses
the energy stored in the sodium gradient (established by the
Na+/K+ ATPase, a primary active transporter) to move another
molecule, like glucose, against its gradient. A is incorrect
because primary active transport uses ATP directly (e.g., the
Na+/K+ pump itself). B is incorrect as diffusion moves
molecules down their concentration gradient without energy
input. D is incorrect as this describes the cellular uptake of large
molecules or complexes.
, Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
solute.
4.
Chapter 1, Section: Cellular Metabolism
A patient in septic shock has cells that are unable to produce
sufficient ATP through aerobic metabolism due to mitochondrial
dysfunction. Which of the following processes would the cells
most rely on to generate a small amount of ATP urgently?
A. Oxidative phosphorylation
B. Beta-oxidation of fatty acids
C. The Krebs (citric acid) cycle
D. Anaerobic glycolysis
Correct Answer: D
Rationale: D is correct because anaerobic glycolysis occurs in
the cytoplasm and does not require oxygen or functional
mitochondria, providing a rapid, though inefficient, source of
ATP. A, B, and C are incorrect because oxidative
phosphorylation, beta-oxidation, and the Krebs cycle are all
components of aerobic metabolism that require functional
mitochondria and oxygen.
Teaching Point: Glycolysis is the primary anaerobic pathway for
ATP production during hypoxia or mitochondrial failure.
5.
Chapter 1, Section: Cellular Communication and Signal
Transduction
The Biologic Basis for Disease in Adults and Children
9th Edition
• Author(s)Julia Rogers
TEST BANK
Chapter 1, Section: 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's primary
action in the signal transduction pathway is to:
A. Phosphorylate tyrosine residues on the receptor itself.
B. Convert ATP to the second messenger cyclic AMP (cAMP).
C. Directly open ion channels to alter the cell's electrical
potential.
D. Cleave membrane phospholipids to produce diacylglycerol
(DAG) and inositol trisphosphate (IP3).
Correct Answer: B
Rationale: B is correct because adenylate cyclase is the key
enzyme that catalyzes the conversion of ATP to cyclic AMP
(cAMP), a ubiquitous second messenger. A is incorrect as this
describes the action of receptor tyrosine kinases, not G-protein
coupled receptors. C is incorrect; while some receptors are
ligand-gated ion channels, this is not the function of adenylate
,cyclase. D is incorrect as this is the function of phospholipase C,
which is activated by a different type of G-protein.
Teaching Point: cAMP is a critical second messenger generated
by adenylate cyclase in response to many first messengers.
2.
Chapter 1, Section: Structure and Function of Cellular
Components
A patient with a rare genetic disorder presents with recurrent
infections and neurological deficits. Diagnostic testing reveals
abnormally large inclusions within lysosomes, suggesting an
impairment in the organelle's ability to break down
macromolecules. The most likely defective cellular structure is
the:
A. Golgi apparatus, which is failing to glycosylate proteins
properly.
B. Peroxisome, which is failing to detoxify free radicals.
C. Lysosome, which is missing specific acid hydrolase enzymes.
D. Rough endoplasmic reticulum, which is failing to synthesize
enzymes.
Correct Answer: C
Rationale: C is correct because lysosomes contain acid
hydrolases responsible for breaking down cellular waste and
pathogens. A deficiency in these enzymes leads to the
accumulation of undigested materials, as seen in lysosomal
storage diseases. A, B, and D are incorrect; while these
organelles are involved in processing, detoxification, and
,synthesis respectively, their dysfunction does not primarily
cause the accumulation of undigested material within the
lysosome itself.
Teaching Point: Lysosomal storage diseases result from
deficient acid hydrolases, causing toxic substrate accumulation.
3.
Chapter 1, Section: 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 directly powered by the sodium-potassium pump and is a
classic example of:
A. Primary active transport.
B. Simple diffusion.
C. Secondary active transport (co-transport).
D. Receptor-mediated endocytosis.
Correct Answer: C
Rationale: C is correct because secondary active transport uses
the energy stored in the sodium gradient (established by the
Na+/K+ ATPase, a primary active transporter) to move another
molecule, like glucose, against its gradient. A is incorrect
because primary active transport uses ATP directly (e.g., the
Na+/K+ pump itself). B is incorrect as diffusion moves
molecules down their concentration gradient without energy
input. D is incorrect as this describes the cellular uptake of large
molecules or complexes.
, Teaching Point: Secondary active transport harnesses the
energy of one ion's gradient to power the movement of another
solute.
4.
Chapter 1, Section: Cellular Metabolism
A patient in septic shock has cells that are unable to produce
sufficient ATP through aerobic metabolism due to mitochondrial
dysfunction. Which of the following processes would the cells
most rely on to generate a small amount of ATP urgently?
A. Oxidative phosphorylation
B. Beta-oxidation of fatty acids
C. The Krebs (citric acid) cycle
D. Anaerobic glycolysis
Correct Answer: D
Rationale: D is correct because anaerobic glycolysis occurs in
the cytoplasm and does not require oxygen or functional
mitochondria, providing a rapid, though inefficient, source of
ATP. A, B, and C are incorrect because oxidative
phosphorylation, beta-oxidation, and the Krebs cycle are all
components of aerobic metabolism that require functional
mitochondria and oxygen.
Teaching Point: Glycolysis is the primary anaerobic pathway for
ATP production during hypoxia or mitochondrial failure.
5.
Chapter 1, Section: Cellular Communication and Signal
Transduction
