Robbins Basic Pathology
10th Edition
Author(s)Vinay Kumar; Abul K. Abbas;
Jon C. Aster
TEST BANK
1.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A newborn fails the newborn screen; genetic testing shows a
frameshift mutation in a crucial enzyme gene. Which cellular
consequence best explains why a frameshift mutation often
produces a nonfunctional protein?
Options
A. Frameshifts typically alter only a single amino acid with
minimal effect on protein folding.
,B. Frameshifts change the reading frame, producing a different
amino acid sequence downstream and often an early stop
codon.
C. Frameshifts remove introns, resulting in failure of translation.
D. Frameshifts increase promoter activity, producing excessive
protein that overwhelms quality control.
Correct Answer
B
Rationales
Correct: Frameshift mutations shift the triplet reading frame,
changing downstream codons and frequently generating
premature stop codons, yielding truncated, nonfunctional
proteins.
A (incorrect): Frameshifts usually alter many amino acids, not
just one, so this statement underestimates the effect.
C (incorrect): Introns are removed by splicing; frameshifts affect
coding sequence, not splicing per se.
D (incorrect): Frameshifts do not increase promoter activity;
they alter the coding sequence, not transcription initiation.
Teaching Point
Frameshift mutations alter the reading frame, often causing
truncated, nonfunctional proteins.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
, 2.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A patient’s tumor harbors loss-of-function mutations in multiple
DNA mismatch–repair genes. Which downstream cellular
phenomenon most directly explains the tumor’s high
mutational burden?
Options
A. Defective removal of bulky DNA adducts formed by reactive
oxygen species.
B. Failure to correct replication errors that generate single base-
pair mismatches and small insertions/deletions.
C. Increased telomerase activity leading to chromosomal
instability.
D. Hyperactivation of nucleotide excision repair creating copy-
number gains.
Correct Answer
B
Rationales
Correct: Mismatch-repair proteins correct replication errors like
base–base mismatches and small indels; loss of these systems
increases mutation rates.
A (incorrect): Repair of bulky adducts is largely nucleotide
excision repair, not mismatch repair.
, C (incorrect): Telomerase activity affects telomere length and
replicative capacity, not primary mismatch correction.
D (incorrect): Nucleotide excision repair does not hyperactivate
to create copy-number gains; it's a different repair pathway.
Teaching Point
Mismatch repair corrects replication mismatches; its loss raises
point mutation and indel rates.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
3.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A clinician interprets a patient’s somatic mosaicism: some
tissues carry a postzygotic mutation, others do not. Which
clinical implication follows from mosaicism?
Options
A. Germline transmission to offspring is guaranteed if
mosaicism is present in any tissue.
B. Phenotypic severity depends on timing and distribution of
the mutation during development.
C. Mosaic mutations always produce milder disease than
germline mutations.
10th Edition
Author(s)Vinay Kumar; Abul K. Abbas;
Jon C. Aster
TEST BANK
1.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A newborn fails the newborn screen; genetic testing shows a
frameshift mutation in a crucial enzyme gene. Which cellular
consequence best explains why a frameshift mutation often
produces a nonfunctional protein?
Options
A. Frameshifts typically alter only a single amino acid with
minimal effect on protein folding.
,B. Frameshifts change the reading frame, producing a different
amino acid sequence downstream and often an early stop
codon.
C. Frameshifts remove introns, resulting in failure of translation.
D. Frameshifts increase promoter activity, producing excessive
protein that overwhelms quality control.
Correct Answer
B
Rationales
Correct: Frameshift mutations shift the triplet reading frame,
changing downstream codons and frequently generating
premature stop codons, yielding truncated, nonfunctional
proteins.
A (incorrect): Frameshifts usually alter many amino acids, not
just one, so this statement underestimates the effect.
C (incorrect): Introns are removed by splicing; frameshifts affect
coding sequence, not splicing per se.
D (incorrect): Frameshifts do not increase promoter activity;
they alter the coding sequence, not transcription initiation.
Teaching Point
Frameshift mutations alter the reading frame, often causing
truncated, nonfunctional proteins.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
, 2.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A patient’s tumor harbors loss-of-function mutations in multiple
DNA mismatch–repair genes. Which downstream cellular
phenomenon most directly explains the tumor’s high
mutational burden?
Options
A. Defective removal of bulky DNA adducts formed by reactive
oxygen species.
B. Failure to correct replication errors that generate single base-
pair mismatches and small insertions/deletions.
C. Increased telomerase activity leading to chromosomal
instability.
D. Hyperactivation of nucleotide excision repair creating copy-
number gains.
Correct Answer
B
Rationales
Correct: Mismatch-repair proteins correct replication errors like
base–base mismatches and small indels; loss of these systems
increases mutation rates.
A (incorrect): Repair of bulky adducts is largely nucleotide
excision repair, not mismatch repair.
, C (incorrect): Telomerase activity affects telomere length and
replicative capacity, not primary mismatch correction.
D (incorrect): Nucleotide excision repair does not hyperactivate
to create copy-number gains; it's a different repair pathway.
Teaching Point
Mismatch repair corrects replication mismatches; its loss raises
point mutation and indel rates.
Citation
Kumar et al. (2021). Robbins Basic Pathology (10th Ed.). Ch. 1.
3.
Reference — Ch. 1 — The Cell as a Unit of Health and Disease
— The Genome
Question Stem
A clinician interprets a patient’s somatic mosaicism: some
tissues carry a postzygotic mutation, others do not. Which
clinical implication follows from mosaicism?
Options
A. Germline transmission to offspring is guaranteed if
mosaicism is present in any tissue.
B. Phenotypic severity depends on timing and distribution of
the mutation during development.
C. Mosaic mutations always produce milder disease than
germline mutations.
