Robbins Basic Pathology
10th Edition
Author(s)Vinay Kumar; MBBS; MD;
FRCPath; Abul K. Abbas; MBBS and
Jon C. Aster; MD; PhD
Print ISBN: 9780323353175
,Question 1
A researcher examines a human cell that has entered a phase of active
protein synthesis. Which cellular structure is primarily responsible for
translating messenger RNA into protein?
A. Lysosome
B. Ribosome
C. Peroxisome
D. Centrosome
,Correct Answer: B. Ribosome
Rationale: Ribosomes translate the nucleotide sequence of messenger
RNA into an amino acid sequence, producing proteins required for
cellular structure and function. Lysosomes digest intracellular
materials, peroxisomes participate in oxidative reactions, and
centrosomes organize microtubules.
Question 2
A patient has a genetic disorder caused by a mutation in a protein-
coding gene. Which sequence most directly explains how the
mutation can produce an abnormal cellular protein?
A. DNA mutation → altered RNA sequence → altered amino acid
sequence
B. DNA mutation → increased lysosomal degradation → altered amino
acid sequence
C. DNA mutation → increased ATP production → altered protein
folding
D. DNA mutation → reduced extracellular matrix synthesis → altered
amino acid sequence
Correct Answer: A. DNA mutation → altered RNA sequence → altered
amino acid sequence
Rationale: A mutation within a protein-coding gene can alter
transcription into RNA and subsequently change the codons that
determine the protein's amino acid sequence. The other sequences do
not represent the direct flow of genetic information from a coding
gene to its protein product.
Question 3
A cell contains damaged proteins that must be removed selectively
, without destroying the entire cell. Which system is primarily
responsible for tagging many intracellular proteins for degradation?
A. Ubiquitin-proteasome system
B. Golgi apparatus
C. Smooth endoplasmic reticulum
D. Nucleolus
Correct Answer: A. Ubiquitin-proteasome system
Rationale: Intracellular proteins that are damaged, misfolded, or no
longer needed can be tagged with ubiquitin and degraded by
proteasomes. The Golgi modifies and sorts proteins, the smooth
endoplasmic reticulum participates in lipid metabolism and
detoxification, and the nucleolus is involved in ribosomal RNA
synthesis and ribosome assembly.
Question 4
A hepatocyte synthesizes a protein that will be secreted into the
bloodstream. Which pathway correctly describes the movement of
this protein?
A. Nucleus → lysosome → plasma membrane
B. Rough endoplasmic reticulum → Golgi apparatus → secretory
vesicle → plasma membrane
C. Smooth endoplasmic reticulum → nucleus → Golgi apparatus
D. Mitochondrion → Golgi apparatus → lysosome → plasma
membrane
Correct Answer: B. Rough endoplasmic reticulum → Golgi apparatus
→ secretory vesicle → plasma membrane
Rationale: Secreted proteins are synthesized on ribosomes attached to
the rough endoplasmic reticulum, transported to the Golgi for
10th Edition
Author(s)Vinay Kumar; MBBS; MD;
FRCPath; Abul K. Abbas; MBBS and
Jon C. Aster; MD; PhD
Print ISBN: 9780323353175
,Question 1
A researcher examines a human cell that has entered a phase of active
protein synthesis. Which cellular structure is primarily responsible for
translating messenger RNA into protein?
A. Lysosome
B. Ribosome
C. Peroxisome
D. Centrosome
,Correct Answer: B. Ribosome
Rationale: Ribosomes translate the nucleotide sequence of messenger
RNA into an amino acid sequence, producing proteins required for
cellular structure and function. Lysosomes digest intracellular
materials, peroxisomes participate in oxidative reactions, and
centrosomes organize microtubules.
Question 2
A patient has a genetic disorder caused by a mutation in a protein-
coding gene. Which sequence most directly explains how the
mutation can produce an abnormal cellular protein?
A. DNA mutation → altered RNA sequence → altered amino acid
sequence
B. DNA mutation → increased lysosomal degradation → altered amino
acid sequence
C. DNA mutation → increased ATP production → altered protein
folding
D. DNA mutation → reduced extracellular matrix synthesis → altered
amino acid sequence
Correct Answer: A. DNA mutation → altered RNA sequence → altered
amino acid sequence
Rationale: A mutation within a protein-coding gene can alter
transcription into RNA and subsequently change the codons that
determine the protein's amino acid sequence. The other sequences do
not represent the direct flow of genetic information from a coding
gene to its protein product.
Question 3
A cell contains damaged proteins that must be removed selectively
, without destroying the entire cell. Which system is primarily
responsible for tagging many intracellular proteins for degradation?
A. Ubiquitin-proteasome system
B. Golgi apparatus
C. Smooth endoplasmic reticulum
D. Nucleolus
Correct Answer: A. Ubiquitin-proteasome system
Rationale: Intracellular proteins that are damaged, misfolded, or no
longer needed can be tagged with ubiquitin and degraded by
proteasomes. The Golgi modifies and sorts proteins, the smooth
endoplasmic reticulum participates in lipid metabolism and
detoxification, and the nucleolus is involved in ribosomal RNA
synthesis and ribosome assembly.
Question 4
A hepatocyte synthesizes a protein that will be secreted into the
bloodstream. Which pathway correctly describes the movement of
this protein?
A. Nucleus → lysosome → plasma membrane
B. Rough endoplasmic reticulum → Golgi apparatus → secretory
vesicle → plasma membrane
C. Smooth endoplasmic reticulum → nucleus → Golgi apparatus
D. Mitochondrion → Golgi apparatus → lysosome → plasma
membrane
Correct Answer: B. Rough endoplasmic reticulum → Golgi apparatus
→ secretory vesicle → plasma membrane
Rationale: Secreted proteins are synthesized on ribosomes attached to
the rough endoplasmic reticulum, transported to the Golgi for
