Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent respiratory
infections, chronic otitis media, and situs inversus. Nasal
epithelial biopsy demonstrates structurally abnormal dynein
arms. The impaired movement of respiratory cilia most directly
disrupts which cellular process?
A. ATP generation through oxidative phosphorylation
B. Cytoskeletal-mediated intracellular transport
C. Passive diffusion across the plasma membrane
D. Ribosomal assembly within the nucleolus
E. Cell-cycle checkpoint regulation
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent sinopulmonary infections with situs inversus strongly
suggests primary ciliary dyskinesia caused by dynein
dysfunction.
Mechanism:
Dynein is a motor protein associated with microtubules that
enables ciliary beating through ATP-dependent cytoskeletal
movement.
Why the Correct Answer Is Right:
Defective dynein arms impair coordinated ciliary motion and
intracellular transport functions dependent on microtubule-
associated motor activity.
Why the Other Options Are Wrong:
A. Mitochondrial ATP production is not the primary defect.
C. Diffusion is independent of dynein-mediated transport.
D. Ribosomal assembly occurs in the nucleolus and is unrelated
to ciliary movement.
E. Cell-cycle checkpoints involve cyclins and tumor suppressor
proteins.
Exam Trap (common misconception tested):
Confusing all ATP-dependent processes with mitochondrial
dysfunction.
,High-Yield Clinical Correlation:
Microtubule motor protein defects impair mucociliary
clearance and fertility due to dysfunctional flagella.
Q2. A researcher exposes hepatocytes to a toxin that selectively
disrupts rough endoplasmic reticulum function. Which
alteration would most likely occur first?
A. Reduced synthesis of secreted plasma proteins
B. Failure of lysosomal hydrolytic activity
C. Impaired β-oxidation of fatty acids
D. Decreased glycogen degradation
E. Inhibition of DNA replication
Correct Answer: A
Rationale:
Clinical Clue:
Hepatocytes rely heavily on rough endoplasmic reticulum for
protein synthesis.
Mechanism:
Ribosomes attached to rough endoplasmic reticulum synthesize
membrane-bound and secreted proteins.
Why the Correct Answer Is Right:
Albumin, clotting factors, and other exported proteins require
intact rough endoplasmic reticulum function for translation and
processing.
, Why the Other Options Are Wrong:
B. Lysosomal dysfunction involves defective lysosomes or Golgi
trafficking.
C. β-oxidation occurs in mitochondria.
D. Glycogen degradation primarily involves cytosolic enzymes.
E. DNA replication occurs in the nucleus.
Exam Trap (common misconception tested):
Confusing smooth and rough endoplasmic reticulum functions.
High-Yield Clinical Correlation:
Drug-induced hepatotoxicity often initially disrupts protein
synthesis before overt cell death develops.
Q3. A patient with severe dehydration develops hypernatremia
with extracellular osmolarity of 325 mOsm/kg. Which
intracellular response is most likely to occur initially?
A. Cellular swelling due to sodium influx
B. Water movement out of cells causing shrinkage
C. Activation of lysosomal rupture within neurons
D. Increased facilitated diffusion of potassium into cells
E. Immediate mitotic arrest in all tissues
Correct Answer: B
Rationale:
Clinical Clue:
Hyperosmolar extracellular fluid draws water out of cells.
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent respiratory
infections, chronic otitis media, and situs inversus. Nasal
epithelial biopsy demonstrates structurally abnormal dynein
arms. The impaired movement of respiratory cilia most directly
disrupts which cellular process?
A. ATP generation through oxidative phosphorylation
B. Cytoskeletal-mediated intracellular transport
C. Passive diffusion across the plasma membrane
D. Ribosomal assembly within the nucleolus
E. Cell-cycle checkpoint regulation
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent sinopulmonary infections with situs inversus strongly
suggests primary ciliary dyskinesia caused by dynein
dysfunction.
Mechanism:
Dynein is a motor protein associated with microtubules that
enables ciliary beating through ATP-dependent cytoskeletal
movement.
Why the Correct Answer Is Right:
Defective dynein arms impair coordinated ciliary motion and
intracellular transport functions dependent on microtubule-
associated motor activity.
Why the Other Options Are Wrong:
A. Mitochondrial ATP production is not the primary defect.
C. Diffusion is independent of dynein-mediated transport.
D. Ribosomal assembly occurs in the nucleolus and is unrelated
to ciliary movement.
E. Cell-cycle checkpoints involve cyclins and tumor suppressor
proteins.
Exam Trap (common misconception tested):
Confusing all ATP-dependent processes with mitochondrial
dysfunction.
,High-Yield Clinical Correlation:
Microtubule motor protein defects impair mucociliary
clearance and fertility due to dysfunctional flagella.
Q2. A researcher exposes hepatocytes to a toxin that selectively
disrupts rough endoplasmic reticulum function. Which
alteration would most likely occur first?
A. Reduced synthesis of secreted plasma proteins
B. Failure of lysosomal hydrolytic activity
C. Impaired β-oxidation of fatty acids
D. Decreased glycogen degradation
E. Inhibition of DNA replication
Correct Answer: A
Rationale:
Clinical Clue:
Hepatocytes rely heavily on rough endoplasmic reticulum for
protein synthesis.
Mechanism:
Ribosomes attached to rough endoplasmic reticulum synthesize
membrane-bound and secreted proteins.
Why the Correct Answer Is Right:
Albumin, clotting factors, and other exported proteins require
intact rough endoplasmic reticulum function for translation and
processing.
, Why the Other Options Are Wrong:
B. Lysosomal dysfunction involves defective lysosomes or Golgi
trafficking.
C. β-oxidation occurs in mitochondria.
D. Glycogen degradation primarily involves cytosolic enzymes.
E. DNA replication occurs in the nucleus.
Exam Trap (common misconception tested):
Confusing smooth and rough endoplasmic reticulum functions.
High-Yield Clinical Correlation:
Drug-induced hepatotoxicity often initially disrupts protein
synthesis before overt cell death develops.
Q3. A patient with severe dehydration develops hypernatremia
with extracellular osmolarity of 325 mOsm/kg. Which
intracellular response is most likely to occur initially?
A. Cellular swelling due to sodium influx
B. Water movement out of cells causing shrinkage
C. Activation of lysosomal rupture within neurons
D. Increased facilitated diffusion of potassium into cells
E. Immediate mitotic arrest in all tissues
Correct Answer: B
Rationale:
Clinical Clue:
Hyperosmolar extracellular fluid draws water out of cells.
