by-Chapter Questions & Verified Solutions
Robbins & Cotran Pathologic Basis of Disease
10th Edition
• Author(s)Vinay Kumar; Abul K. Abbas; Jon C. Aster
1. Cellular Housekeeping
A 67-year-old patient with a long-term smoking history is diagnosed with emphysema.
Pathological examination reveals intracellular accumulation of damaged cellular
components. A defect in which of the following cellular housekeeping processes is most
directly responsible for this finding?
A. Ubiquitin-proteasome degradation
B. Autophagy
C. Endocytosis
D. DNA damage repair
Correct Answer: B
Rationale: Autophagy is the primary process for degrading and recycling damaged
organelles and long-lived proteins, forming a critical quality control mechanism.
Impairment leads to the accumulation of toxic cellular debris, which is implicated in
degenerative diseases. The other options are incorrect: A deals with short-lived proteins,
C is for internalizing extracellular material, and D is for maintaining genomic integrity,
not cytoplasmic cleanliness.
Teaching Point: Autophagy clears damaged organelles; its failure causes toxic
accumulation.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1: Cellular
Housekeeping.
,2. Cellular Metabolism and Mitochondrial Function
A researcher is studying a cell line with a genetic mutation that disrupts the integrity of
the inner mitochondrial membrane cristae. Which of the following cellular functions is
most directly and severely compromised by this structural defect?
A. Synthesis of phospholipids for membrane biogenesis
B. Generation of adenosine triphosphate (ATP) via oxidative phosphorylation
C. Detoxification of reactive oxygen species (ROS) by catalase
D. Storage and release of intracellular calcium ions
Correct Answer: B
Rationale: The cristae greatly increase the surface area of the inner mitochondrial
membrane, which is where the electron transport chain complexes and ATP synthase are
located. Damage to cristae structure directly impairs the efficiency of oxidative
phosphorylation. The other options are not primarily functions of the mitochondrial
cristae: A occurs in the endoplasmic reticulum, C is primarily a peroxisomal function, and
D, while mitochondria participate in calcium buffering, it is not their primary energy-
generating function.
Teaching Point: Mitochondrial cristae are essential for efficient ATP production via
oxidative phosphorylation.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1: Cellular
Metabolism and Mitochondrial Function.
3. The Genome
A patient is found to have a disease caused by a mutation in a gene that regulates
chromatin structure by adding acetyl groups to histones. This mutation most directly
affects which of the following genomic processes?
A. The accuracy of DNA replication during the S phase
B. The repair of double-stranded DNA breaks
C. The accessibility of DNA for transcription
D. The segregation of chromosomes during mitosis
Correct Answer: C
Rationale: Histone acetylation is a key epigenetic mechanism that loosens chromatin
structure, making DNA more accessible to transcription factors and RNA polymerase,
thereby promoting gene expression. The other options are incorrect: A, B, and D are
processes involving the DNA sequence itself or the mitotic apparatus, not primarily the
regulation of gene expression via chromatin remodeling.
Teaching Point: Epigenetic modifications like histone acetylation regulate gene
,expression by altering DNA accessibility.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1: The
Genome.
4. Growth Factors and Receptors
A new chemotherapeutic agent is designed to block the tyrosine kinase activity of a
growth factor receptor that is overexpressed in a certain cancer. This agent would most
directly prevent which of the following steps in the signaling cascade?
A. Dimerization of the receptor upon ligand binding
B. Initiation of the transcription of growth-promoting genes
C. Autophosphorylation of the receptor and recruitment of signaling proteins
D. Internalization and degradation of the receptor-ligand complex
Correct Answer: C
Rationale: For many receptor tyrosine kinases (RTKs), ligand binding induces
dimerization and autophosphorylation, which creates docking sites for intracellular
signaling proteins (e.g., RAS, PI3K). Blocking kinase activity directly inhibits this key early
step. The other options are incorrect: A may still occur but signaling is blocked, B is a
downstream consequence, and D is a termination mechanism.
Teaching Point: Tyrosine kinase inhibitors block signal transduction by preventing
receptor autophosphorylation.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1: Growth
Factors and Receptors.
5. Extracellular Matrix
A genetic disorder impairs the synthesis of fibrillar collagen. A biopsy of the patient's
skin would likely show abnormalities in which of the following properties of the
connective tissue?
A. Resilience and the ability to return to a resting shape after deformation
B. Resistance to tensile forces (stretching and tearing)
C. Lubrication and compression resistance of articular surfaces
D. Adhesion of epithelial cells to the underlying basement membrane
Correct Answer: B
Rationale: Fibrillar collagens (e.g., Type I, III) provide the ECM with high tensile strength,
forming a rigid scaffold. A defect would directly lead to fragile, easily torn skin. The
other options are functions of other ECM components: A is more related to elastin, C to
, proteoglycans, and D to adhesion proteins like laminin in the basement membrane.
Teaching Point: Collagen provides tensile strength to tissues, while elastin provides
elasticity.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1:
Extracellular Matrix.
6. Maintaining Cell Populations
A patient with aplastic anemia has a marked decrease in blood cell counts. This
condition results primarily from a failure in which of the following cellular processes?
A. The self-renewal and differentiation of tissue stem cells
B. The programmed cell death of mature, effete cells
C. The hypertrophy of existing progenitor cells in the bone marrow
D. The metaplastic transformation of stromal cells into hematopoietic cells
Correct Answer: A
Rationale: The maintenance of differentiated cell populations, like blood cells, depends
on the continuous division and differentiation of tissue-specific stem cells
(hematopoietic stem cells in this case). Aplastic anemia is a classic example of stem cell
failure. The other options are incorrect: B would not explain a failure to produce cells, C
is an increase in cell size, not number, and D is an abnormal change in cell type, not a
normal maintenance mechanism.
Teaching Point: Tissue stem cells are essential for replenishing mature, short-lived cell
populations.
Citation: Robbins & Cotran Pathologic Basis of Disease, 10th Ed., Chapter 1: Maintaining
Cell Populations.
7. Cellular Metabolism and Mitochondrial Function
In addition to producing ATP, mitochondria play a key role in regulating a specific form
of programmed cell death. This regulatory function is primarily mediated through the
controlled release of which of the following substances from the mitochondrial
intermembrane space into the cytoplasm?
A. Cytochrome c
B. ATP synthase
C. Citric acid cycle enzymes
D. Mitochondrial DNA