Robbins & Cotran 10th Ed. Pathology Test Bank | Chapter-
by-Chapter Questions & Verified Solutions
Robbins & Cotran Pathologic Basis of Disease
10th Edition
• Author(s)Vinay Kumar; Abul K. Abbas; Jon C. Aster
1.
Chapter Reference – Chapter 1: The Cell as a Unit of Health
and Disease — The Genome
Stem: A 40-year-old woman with chronic congestive heart
failure presents with a cough productive of rust-colored sputum.
Cytology of the sputum is expected to show numerous
macrophages filled with hemosiderin. The accumulation of this
iron-storage complex within the macrophage's cytoplasm is most
directly due to the action of which cellular component?
Options:
A. Endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Ribosome
Correct Answer: C. Lysosome
Rationale:
, • Correct: The breakdown of red blood cells and their
hemoglobin by macrophages occurs through phagocytosis.
The engulfed material is degraded within phagolysosomes,
which are vesicles formed by the fusion of the phagosome
with lysosomes containing digestive enzymes. Hemosiderin
is an insoluble derivative of hemoglobin that accumulates
within these structures.
• Incorrect A: The endoplasmic reticulum is involved in
protein and lipid synthesis, not the degradation of
phagocytosed material.
• Incorrect B: The Golgi apparatus modifies, sorts, and
packages proteins for secretion or transport to other
organelles; it is not primarily involved in degradation.
• Incorrect D: Ribosomes are responsible for protein
synthesis and are not involved in the phagocytic breakdown
of extracellular pigments.
Teaching Point: Lysosomes are the primary organelles for
intracellular digestion and degradation of phagocytosed
material.
Question 2
Chapter & Section: Cellular Housekeeping
Stem: In an experiment, cells subjected to ultraviolet radiation
show cytosolic aggregates of denatured proteins. Analysis
reveals that protein components in these aggregates are also
found in proteasomes. Which of the following substances most
,directly tags these damaged proteins for destruction by the
proteasomal pathway?
Options:
A. Caspase
B. Glutathione
C. Sirtuins
D. Ubiquitin
Correct Answer: D. Ubiquitin
Rationale:
• Correct: The ubiquitin-proteasome system is a key
mechanism for degrading misfolded or damaged
intracellular proteins. Ubiquitin molecules are covalently
attached to target proteins, marking them for recognition
and proteolysis by the proteasome.
• Incorrect A: Caspases are enzymes that execute
programmed cell death (apoptosis), not targeted protein
degradation.
• Incorrect B: Glutathione is an antioxidant that helps
neutralize free radicals, protecting proteins from damage,
but it does not tag them for degradation.
• Incorrect C: Sirtuins are involved in gene silencing and
aging through histone deacetylation, not the direct tagging
of proteins for breakdown.
Teaching Point: Ubiquitin acts as a molecular tag that
targets abnormal proteins for degradation by proteasomes, a
critical housekeeping function.
,Question 3
Chapter & Section: Cellular Metabolism and Mitochondrial
Function
Stem: A patient presents with a rare genetic disorder
characterized by progressive neurodegeneration and lactic
acidosis. A defect in which of the following mitochondrial
components would most directly impair the conversion of the
proton gradient into cellular energy (ATP)?
Options:
A. Complex I (NADH dehydrogenase)
B. Complex III (Cytochrome c reductase)
C. Complex IV (Cytochrome c oxidase)
D. Complex V (ATP synthase)
Correct Answer: D. Complex V (ATP synthase)
Rationale:
• Correct: The proton gradient across the inner
mitochondrial membrane, generated by the electron
transport chain (Complexes I-IV), creates an
electrochemical potential. ATP synthase (Complex V) uses
the energy from protons flowing back down this gradient to
phosphorylate ADP, producing ATP.
• Incorrect A, B, & C: These complexes (I, III, and IV) are
responsible for establishing the proton gradient by pumping
protons into the intermembrane space. They do not directly
synthesize ATP.
Teaching Point: ATP synthase (Complex V) is the enzyme
that harnesses the proton-motive force to synthesize ATP,
linking the electron transport chain to energy production.
,Question 4
Chapter & Section: Growth Factors and Receptors
Stem: At the site of a healing surgical wound, endothelial cells
migrate to form new capillaries in response to vascular
endothelial growth factor (VEGF). Which of the following
intracellular proteins is most critical for the cytoskeletal changes
required for this cell movement?
Options:
A. Cytokeratin
B. Desmin
C. Actin
D. Lamin
Correct Answer: C. Actin
Rationale:
• Correct: Cell migration depends on the dynamic assembly
and disassembly of actin microfilaments. Actin
polymerization drives the formation of cellular protrusions
like lamellipodia, which are essential for cell movement.
• Incorrect A & B: Cytokeratin and desmin are types of
intermediate filaments that provide mechanical strength to
epithelial and muscle cells, respectively. They are not
primarily involved in motility.
• Incorrect D: Lamin is an intermediate filament that
provides structural support to the nuclear envelope, not the
cytoplasm.
Teaching Point: Actin microfilaments form the dynamic
, cytoskeletal network essential for cell motility and
migration.
Question 5
Chapter & Section: Growth Factors and Receptors
Stem: When epidermal growth factor (EGF) binds to its
receptor on the cell surface, it triggers a signal transduction
pathway that ultimately leads to DNA transcription and cell
division. Which of the following pathways is most directly
involved in transducing this mitogenic signal from the
membrane to the nucleus?
Options:
A. Cyclic AMP pathway
B. JAK/STAT system
C. Mitogen-activated protein (MAP) kinase cascade
D. Calcium ion channel activation
Correct Answer: C. Mitogen-activated protein (MAP) kinase
cascade
Rationale:
• Correct: The MAP kinase pathway is a primary signaling
cascade activated by receptor tyrosine kinases, such as the
EGF receptor. This pathway relays the growth signal from
the membrane through a series of phosphorylation events,
ultimately leading to the activation of transcription factors
in the nucleus.
, • Incorrect A: The cyclic AMP pathway is typically
associated with G-protein coupled receptors, not directly
with receptor tyrosine kinases like the EGF receptor.
• Incorrect B: The JAK/STAT pathway is primarily used by
cytokine receptors.
• Incorrect D: Calcium channel activation can be a second
messenger in various pathways but is not the primary route
for EGF signal transduction.
Teaching Point: The MAP kinase cascade is a key
intracellular pathway that transduces mitogenic signals
from growth factor receptors to the nucleus.
Question 6
Chapter & Section: Extracellular Matrix
Stem: A 62-year-old man with osteoarthritis shows erosion of
the articular cartilage in his knee joint, leading to a loss of
compressibility and shock absorption. This change is most
directly attributed to a deficiency in which extracellular matrix
component?
Options:
A. Collagen type II
B. Elastin
C. Fibronectin
D. Hyaluronan
Correct Answer: D. Hyaluronan
Rationale:
, • Correct: Hyaluronan (hyaluronic acid) is a major
component of proteoglycans in cartilage. It forms a
hydrated, viscous gel that provides compressibility and
lubrication, which are critical for the function of articular
surfaces.
• Incorrect A: While collagen type II provides tensile
strength to cartilage, its loss would not primarily affect
compressibility.
• Incorrect B: Elastin provides elasticity to tissues like
blood vessels and skin, but it is not a major component
responsible for the shock-absorbing quality of cartilage.
• Incorrect C: Fibronectin is important for cell adhesion and
migration but does not contribute significantly to the
biomechanical compressibility of cartilage.
Teaching Point: Hyaluronan provides the hydrated gel that
gives cartilage its ability to resist compression.
Question 7
Chapter & Section: Extracellular Matrix
Stem: The extracellular matrix (ECM) serves as a reservoir for
certain growth factors. How does the binding of fibroblast
growth factor (FGF) to heparan sulfate proteoglycans in the
ECM primarily influence FGF activity?
Options:
A. It permanently inactivates FGF.
B. It protects FGF from degradation and facilitates its
,presentation to the receptor.
C. It directly transports FGF into the cell cytoplasm.
D. It converts FGF into an intracellular signaling molecule.
Correct Answer: B. It protects FGF from degradation and
facilitates its presentation to the receptor.
Rationale:
• Correct: Storing growth factors like FGF in the ECM
protects them from proteolytic degradation. Furthermore,
interaction with heparan sulfate is often required for the
effective formation of the FGF signaling complex with its
receptor on the cell surface.
• Incorrect A: The binding is reversible and regulatory, not
permanently inactivating.
• Incorrect C & D: The ECM stores growth factors
extracellularly; it does not directly transport them into the
cell or change their fundamental nature.
Teaching Point: ECM proteoglycans regulate growth
factor bioavailability by controlling storage, stability, and
receptor binding.
Question 8
Chapter & Section: The Genome
Stem: Analysis of a peripheral blood smear shows that the
neutrophil nuclei of women have a Barr body, an inactivated X
chromosome. Which type of RNA is most responsible for
initiating and maintaining this form of gene silencing?
, Options:
A. Messenger RNA (mRNA)
B. MicroRNA (miRNA)
C. Long noncoding RNA (lncRNA)
D. Transfer RNA (tRNA)
Correct Answer: C. Long noncoding RNA (lncRNA)
Rationale:
• Correct: The inactivation of one X chromosome in female
cells is initiated by the lncRNA called XIST. XIST is
transcribed from the X chromosome that will be inactivated
and coats it, leading to chromatin modification and gene
silencing.
• Incorrect A: mRNA carries the genetic code for protein
synthesis and does not silence chromosomes.
• Incorrect B: miRNA primarily functions by inhibiting the
translation or promoting the degradation of specific mRNA
molecules, not by silencing entire chromosomes.
• Incorrect D: tRNA is involved in bringing amino acids to
the ribosome during protein translation.
Teaching Point: Long noncoding RNAs like XIST can
silence large chromosomal regions by modifying chromatin
structure.
Additional Questions (9-20)
by-Chapter Questions & Verified Solutions
Robbins & Cotran Pathologic Basis of Disease
10th Edition
• Author(s)Vinay Kumar; Abul K. Abbas; Jon C. Aster
1.
Chapter Reference – Chapter 1: The Cell as a Unit of Health
and Disease — The Genome
Stem: A 40-year-old woman with chronic congestive heart
failure presents with a cough productive of rust-colored sputum.
Cytology of the sputum is expected to show numerous
macrophages filled with hemosiderin. The accumulation of this
iron-storage complex within the macrophage's cytoplasm is most
directly due to the action of which cellular component?
Options:
A. Endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Ribosome
Correct Answer: C. Lysosome
Rationale:
, • Correct: The breakdown of red blood cells and their
hemoglobin by macrophages occurs through phagocytosis.
The engulfed material is degraded within phagolysosomes,
which are vesicles formed by the fusion of the phagosome
with lysosomes containing digestive enzymes. Hemosiderin
is an insoluble derivative of hemoglobin that accumulates
within these structures.
• Incorrect A: The endoplasmic reticulum is involved in
protein and lipid synthesis, not the degradation of
phagocytosed material.
• Incorrect B: The Golgi apparatus modifies, sorts, and
packages proteins for secretion or transport to other
organelles; it is not primarily involved in degradation.
• Incorrect D: Ribosomes are responsible for protein
synthesis and are not involved in the phagocytic breakdown
of extracellular pigments.
Teaching Point: Lysosomes are the primary organelles for
intracellular digestion and degradation of phagocytosed
material.
Question 2
Chapter & Section: Cellular Housekeeping
Stem: In an experiment, cells subjected to ultraviolet radiation
show cytosolic aggregates of denatured proteins. Analysis
reveals that protein components in these aggregates are also
found in proteasomes. Which of the following substances most
,directly tags these damaged proteins for destruction by the
proteasomal pathway?
Options:
A. Caspase
B. Glutathione
C. Sirtuins
D. Ubiquitin
Correct Answer: D. Ubiquitin
Rationale:
• Correct: The ubiquitin-proteasome system is a key
mechanism for degrading misfolded or damaged
intracellular proteins. Ubiquitin molecules are covalently
attached to target proteins, marking them for recognition
and proteolysis by the proteasome.
• Incorrect A: Caspases are enzymes that execute
programmed cell death (apoptosis), not targeted protein
degradation.
• Incorrect B: Glutathione is an antioxidant that helps
neutralize free radicals, protecting proteins from damage,
but it does not tag them for degradation.
• Incorrect C: Sirtuins are involved in gene silencing and
aging through histone deacetylation, not the direct tagging
of proteins for breakdown.
Teaching Point: Ubiquitin acts as a molecular tag that
targets abnormal proteins for degradation by proteasomes, a
critical housekeeping function.
,Question 3
Chapter & Section: Cellular Metabolism and Mitochondrial
Function
Stem: A patient presents with a rare genetic disorder
characterized by progressive neurodegeneration and lactic
acidosis. A defect in which of the following mitochondrial
components would most directly impair the conversion of the
proton gradient into cellular energy (ATP)?
Options:
A. Complex I (NADH dehydrogenase)
B. Complex III (Cytochrome c reductase)
C. Complex IV (Cytochrome c oxidase)
D. Complex V (ATP synthase)
Correct Answer: D. Complex V (ATP synthase)
Rationale:
• Correct: The proton gradient across the inner
mitochondrial membrane, generated by the electron
transport chain (Complexes I-IV), creates an
electrochemical potential. ATP synthase (Complex V) uses
the energy from protons flowing back down this gradient to
phosphorylate ADP, producing ATP.
• Incorrect A, B, & C: These complexes (I, III, and IV) are
responsible for establishing the proton gradient by pumping
protons into the intermembrane space. They do not directly
synthesize ATP.
Teaching Point: ATP synthase (Complex V) is the enzyme
that harnesses the proton-motive force to synthesize ATP,
linking the electron transport chain to energy production.
,Question 4
Chapter & Section: Growth Factors and Receptors
Stem: At the site of a healing surgical wound, endothelial cells
migrate to form new capillaries in response to vascular
endothelial growth factor (VEGF). Which of the following
intracellular proteins is most critical for the cytoskeletal changes
required for this cell movement?
Options:
A. Cytokeratin
B. Desmin
C. Actin
D. Lamin
Correct Answer: C. Actin
Rationale:
• Correct: Cell migration depends on the dynamic assembly
and disassembly of actin microfilaments. Actin
polymerization drives the formation of cellular protrusions
like lamellipodia, which are essential for cell movement.
• Incorrect A & B: Cytokeratin and desmin are types of
intermediate filaments that provide mechanical strength to
epithelial and muscle cells, respectively. They are not
primarily involved in motility.
• Incorrect D: Lamin is an intermediate filament that
provides structural support to the nuclear envelope, not the
cytoplasm.
Teaching Point: Actin microfilaments form the dynamic
, cytoskeletal network essential for cell motility and
migration.
Question 5
Chapter & Section: Growth Factors and Receptors
Stem: When epidermal growth factor (EGF) binds to its
receptor on the cell surface, it triggers a signal transduction
pathway that ultimately leads to DNA transcription and cell
division. Which of the following pathways is most directly
involved in transducing this mitogenic signal from the
membrane to the nucleus?
Options:
A. Cyclic AMP pathway
B. JAK/STAT system
C. Mitogen-activated protein (MAP) kinase cascade
D. Calcium ion channel activation
Correct Answer: C. Mitogen-activated protein (MAP) kinase
cascade
Rationale:
• Correct: The MAP kinase pathway is a primary signaling
cascade activated by receptor tyrosine kinases, such as the
EGF receptor. This pathway relays the growth signal from
the membrane through a series of phosphorylation events,
ultimately leading to the activation of transcription factors
in the nucleus.
, • Incorrect A: The cyclic AMP pathway is typically
associated with G-protein coupled receptors, not directly
with receptor tyrosine kinases like the EGF receptor.
• Incorrect B: The JAK/STAT pathway is primarily used by
cytokine receptors.
• Incorrect D: Calcium channel activation can be a second
messenger in various pathways but is not the primary route
for EGF signal transduction.
Teaching Point: The MAP kinase cascade is a key
intracellular pathway that transduces mitogenic signals
from growth factor receptors to the nucleus.
Question 6
Chapter & Section: Extracellular Matrix
Stem: A 62-year-old man with osteoarthritis shows erosion of
the articular cartilage in his knee joint, leading to a loss of
compressibility and shock absorption. This change is most
directly attributed to a deficiency in which extracellular matrix
component?
Options:
A. Collagen type II
B. Elastin
C. Fibronectin
D. Hyaluronan
Correct Answer: D. Hyaluronan
Rationale:
, • Correct: Hyaluronan (hyaluronic acid) is a major
component of proteoglycans in cartilage. It forms a
hydrated, viscous gel that provides compressibility and
lubrication, which are critical for the function of articular
surfaces.
• Incorrect A: While collagen type II provides tensile
strength to cartilage, its loss would not primarily affect
compressibility.
• Incorrect B: Elastin provides elasticity to tissues like
blood vessels and skin, but it is not a major component
responsible for the shock-absorbing quality of cartilage.
• Incorrect C: Fibronectin is important for cell adhesion and
migration but does not contribute significantly to the
biomechanical compressibility of cartilage.
Teaching Point: Hyaluronan provides the hydrated gel that
gives cartilage its ability to resist compression.
Question 7
Chapter & Section: Extracellular Matrix
Stem: The extracellular matrix (ECM) serves as a reservoir for
certain growth factors. How does the binding of fibroblast
growth factor (FGF) to heparan sulfate proteoglycans in the
ECM primarily influence FGF activity?
Options:
A. It permanently inactivates FGF.
B. It protects FGF from degradation and facilitates its
,presentation to the receptor.
C. It directly transports FGF into the cell cytoplasm.
D. It converts FGF into an intracellular signaling molecule.
Correct Answer: B. It protects FGF from degradation and
facilitates its presentation to the receptor.
Rationale:
• Correct: Storing growth factors like FGF in the ECM
protects them from proteolytic degradation. Furthermore,
interaction with heparan sulfate is often required for the
effective formation of the FGF signaling complex with its
receptor on the cell surface.
• Incorrect A: The binding is reversible and regulatory, not
permanently inactivating.
• Incorrect C & D: The ECM stores growth factors
extracellularly; it does not directly transport them into the
cell or change their fundamental nature.
Teaching Point: ECM proteoglycans regulate growth
factor bioavailability by controlling storage, stability, and
receptor binding.
Question 8
Chapter & Section: The Genome
Stem: Analysis of a peripheral blood smear shows that the
neutrophil nuclei of women have a Barr body, an inactivated X
chromosome. Which type of RNA is most responsible for
initiating and maintaining this form of gene silencing?
, Options:
A. Messenger RNA (mRNA)
B. MicroRNA (miRNA)
C. Long noncoding RNA (lncRNA)
D. Transfer RNA (tRNA)
Correct Answer: C. Long noncoding RNA (lncRNA)
Rationale:
• Correct: The inactivation of one X chromosome in female
cells is initiated by the lncRNA called XIST. XIST is
transcribed from the X chromosome that will be inactivated
and coats it, leading to chromatin modification and gene
silencing.
• Incorrect A: mRNA carries the genetic code for protein
synthesis and does not silence chromosomes.
• Incorrect B: miRNA primarily functions by inhibiting the
translation or promoting the degradation of specific mRNA
molecules, not by silencing entire chromosomes.
• Incorrect D: tRNA is involved in bringing amino acids to
the ribosome during protein translation.
Teaching Point: Long noncoding RNAs like XIST can
silence large chromosomal regions by modifying chromatin
structure.
Additional Questions (9-20)
