Robbins Basic Pathology
10th Edition
Author(s)Vinay Kumar; Abul K. Abbas;
Jon C. Aster
TEST BANK
1.
Reference
– Ch. 1 — The Genome
Question Stem
A 28-year-old woman planning pregnancy is found to carry
a BRCA1 frameshift variant that truncates the protein.
Which molecular consequence most likely explains how
this variant increases disease risk?
Options
A. Increased formation of double-strand breaks due to loss
of base excision repair
,B. Impaired homologous recombination repair leading to
genomic instability
C. Increased transcription of oncogenes from promoter
demethylation
D. Constitutive activation of a receptor tyrosine kinase
causing proliferative signaling
Correct Answer
B
Rationales
Correct: Loss of BRCA1 function disrupts homologous
recombination repair of double-strand breaks, promoting
chromosomal instability and cancer risk.
A: Base excision repair primarily corrects single-base
lesions, not the key BRCA1 pathway.
C: Promoter demethylation increasing oncogene
transcription is an epigenetic mechanism not directly
caused by BRCA1 truncation.
D: Constitutive RTK activation is a signaling mechanism
unrelated to BRCA1’s DNA repair role.
Teaching Point
BRCA1 loss → defective homologous recombination →
genomic instability.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.).
Ch. 1.
,2.
Reference
– Ch. 1 — The Genome
Question Stem
A patient’s tumor sequencing shows a nonsense mutation
in a tumor suppressor gene producing a premature stop
codon. Which cellular mechanism most directly prevents
accumulation of the truncated, potentially harmful
protein?
Options
A. Nonsense-mediated mRNA decay targeting the aberrant
transcript
B. Mismatch repair correcting the point mutation at the
DNA level
C. Ubiquitin–proteasome degradation of the truncated
polypeptide only after translation
D. Base excision repair removing the stop codon
Correct Answer
A
Rationales
Correct: Nonsense-mediated mRNA decay detects
premature termination codons and degrades the mRNA,
preventing production of truncated proteins.
B: Mismatch repair corrects replication errors but does not
, remove already established nonsense mutations in mRNA.
C: The proteasome degrades proteins but NMD acts earlier
by eliminating faulty mRNA before translation.
D: Base excision repair fixes small base lesions, not
premature stop codons in mRNA.
Teaching Point
Nonsense-mediated decay eliminates mRNAs with
premature stop codons.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.).
Ch. 1.
3.
Reference
– Ch. 1 — Cellular Housekeeping
Question Stem
A 65-year-old man with chronic alcohol use develops
macrovesicular hepatic steatosis. Dysfunction in which
cellular housekeeping pathway most directly contributes to
accumulation of lipid droplets in hepatocytes?
Options
A. Impaired autophagy–lysosomal degradation of lipid
stores
B. Defective mitochondrial fission increasing fatty acid
oxidation
10th Edition
Author(s)Vinay Kumar; Abul K. Abbas;
Jon C. Aster
TEST BANK
1.
Reference
– Ch. 1 — The Genome
Question Stem
A 28-year-old woman planning pregnancy is found to carry
a BRCA1 frameshift variant that truncates the protein.
Which molecular consequence most likely explains how
this variant increases disease risk?
Options
A. Increased formation of double-strand breaks due to loss
of base excision repair
,B. Impaired homologous recombination repair leading to
genomic instability
C. Increased transcription of oncogenes from promoter
demethylation
D. Constitutive activation of a receptor tyrosine kinase
causing proliferative signaling
Correct Answer
B
Rationales
Correct: Loss of BRCA1 function disrupts homologous
recombination repair of double-strand breaks, promoting
chromosomal instability and cancer risk.
A: Base excision repair primarily corrects single-base
lesions, not the key BRCA1 pathway.
C: Promoter demethylation increasing oncogene
transcription is an epigenetic mechanism not directly
caused by BRCA1 truncation.
D: Constitutive RTK activation is a signaling mechanism
unrelated to BRCA1’s DNA repair role.
Teaching Point
BRCA1 loss → defective homologous recombination →
genomic instability.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.).
Ch. 1.
,2.
Reference
– Ch. 1 — The Genome
Question Stem
A patient’s tumor sequencing shows a nonsense mutation
in a tumor suppressor gene producing a premature stop
codon. Which cellular mechanism most directly prevents
accumulation of the truncated, potentially harmful
protein?
Options
A. Nonsense-mediated mRNA decay targeting the aberrant
transcript
B. Mismatch repair correcting the point mutation at the
DNA level
C. Ubiquitin–proteasome degradation of the truncated
polypeptide only after translation
D. Base excision repair removing the stop codon
Correct Answer
A
Rationales
Correct: Nonsense-mediated mRNA decay detects
premature termination codons and degrades the mRNA,
preventing production of truncated proteins.
B: Mismatch repair corrects replication errors but does not
, remove already established nonsense mutations in mRNA.
C: The proteasome degrades proteins but NMD acts earlier
by eliminating faulty mRNA before translation.
D: Base excision repair fixes small base lesions, not
premature stop codons in mRNA.
Teaching Point
Nonsense-mediated decay eliminates mRNAs with
premature stop codons.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.).
Ch. 1.
3.
Reference
– Ch. 1 — Cellular Housekeeping
Question Stem
A 65-year-old man with chronic alcohol use develops
macrovesicular hepatic steatosis. Dysfunction in which
cellular housekeeping pathway most directly contributes to
accumulation of lipid droplets in hepatocytes?
Options
A. Impaired autophagy–lysosomal degradation of lipid
stores
B. Defective mitochondrial fission increasing fatty acid
oxidation
