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 identifies a mutation in a somatic cell that changes the
amino acid sequence of a protein involved in intracellular signaling.
Which cellular structure contains the DNA sequence that ultimately
determines the altered amino acid sequence?
A. Lysosome
B. Genome
C. Golgi apparatus
D. Extracellular matrix
,Correct Answer: B. Genome
Rationale: The genome contains the cell's complete genetic
information, including genes that encode proteins. A lysosome is
involved in intracellular degradation, the Golgi modifies and sorts
proteins, and the extracellular matrix is composed of molecules outside
cells rather than hereditary DNA.
Question 2
A patient has a hereditary disorder caused by a mutation present in
virtually every cell of the body. Which characteristic best explains why
the abnormality can be transmitted to offspring?
A. The mutation is confined to differentiated muscle cells
B. The mutation alters extracellular collagen after birth
C. The mutation is present in the germline
D. The mutation affects only mitochondrial ATP production in
hepatocytes
Correct Answer: C. The mutation is present in the germline
Rationale: Germline mutations can be incorporated into gametes and
therefore transmitted to subsequent generations. A somatic mutation
limited to muscle is not generally inherited. Altered collagen production
after birth is not itself a mechanism of genetic transmission, and a
hepatocyte-specific mitochondrial abnormality is somatic.
Question 3
A cell produces a protein that must be secreted into the extracellular
environment. Which cellular process is most directly responsible for
directing the newly synthesized protein into the appropriate
intracellular pathway?
, A. Translation on free ribosomes followed by lysosomal degradation
B. Translation on ribosomes associated with the rough endoplasmic
reticulum
C. Replication of mitochondrial DNA
D. Synthesis of ATP within the cytosol
Correct Answer: B. Translation on ribosomes associated with the rough
endoplasmic reticulum
Rationale: Proteins destined for secretion are synthesized on ribosomes
attached to the rough endoplasmic reticulum and then enter the
secretory pathway. Free ribosomes primarily synthesize cytosolic
proteins, mitochondrial DNA replication does not direct secretory
proteins, and ATP production does not determine protein trafficking.
Question 4
A cell is exposed to a toxic compound that markedly increases oxidative
damage to proteins and organelles. Which organelle is primarily
responsible for degrading damaged intracellular proteins and cellular
components through a controlled intracellular degradation system?
A. Proteasome
B. Nucleolus
C. Centrosome
D. Golgi apparatus
Correct Answer: A. Proteasome
Rationale: The proteasome degrades damaged or unwanted
intracellular proteins, particularly those tagged for destruction. The
nucleolus is involved in ribosome production, the centrosome organizes
microtubules, and the Golgi modifies and sorts proteins.
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 identifies a mutation in a somatic cell that changes the
amino acid sequence of a protein involved in intracellular signaling.
Which cellular structure contains the DNA sequence that ultimately
determines the altered amino acid sequence?
A. Lysosome
B. Genome
C. Golgi apparatus
D. Extracellular matrix
,Correct Answer: B. Genome
Rationale: The genome contains the cell's complete genetic
information, including genes that encode proteins. A lysosome is
involved in intracellular degradation, the Golgi modifies and sorts
proteins, and the extracellular matrix is composed of molecules outside
cells rather than hereditary DNA.
Question 2
A patient has a hereditary disorder caused by a mutation present in
virtually every cell of the body. Which characteristic best explains why
the abnormality can be transmitted to offspring?
A. The mutation is confined to differentiated muscle cells
B. The mutation alters extracellular collagen after birth
C. The mutation is present in the germline
D. The mutation affects only mitochondrial ATP production in
hepatocytes
Correct Answer: C. The mutation is present in the germline
Rationale: Germline mutations can be incorporated into gametes and
therefore transmitted to subsequent generations. A somatic mutation
limited to muscle is not generally inherited. Altered collagen production
after birth is not itself a mechanism of genetic transmission, and a
hepatocyte-specific mitochondrial abnormality is somatic.
Question 3
A cell produces a protein that must be secreted into the extracellular
environment. Which cellular process is most directly responsible for
directing the newly synthesized protein into the appropriate
intracellular pathway?
, A. Translation on free ribosomes followed by lysosomal degradation
B. Translation on ribosomes associated with the rough endoplasmic
reticulum
C. Replication of mitochondrial DNA
D. Synthesis of ATP within the cytosol
Correct Answer: B. Translation on ribosomes associated with the rough
endoplasmic reticulum
Rationale: Proteins destined for secretion are synthesized on ribosomes
attached to the rough endoplasmic reticulum and then enter the
secretory pathway. Free ribosomes primarily synthesize cytosolic
proteins, mitochondrial DNA replication does not direct secretory
proteins, and ATP production does not determine protein trafficking.
Question 4
A cell is exposed to a toxic compound that markedly increases oxidative
damage to proteins and organelles. Which organelle is primarily
responsible for degrading damaged intracellular proteins and cellular
components through a controlled intracellular degradation system?
A. Proteasome
B. Nucleolus
C. Centrosome
D. Golgi apparatus
Correct Answer: A. Proteasome
Rationale: The proteasome degrades damaged or unwanted
intracellular proteins, particularly those tagged for destruction. The
nucleolus is involved in ribosome production, the centrosome organizes
microtubules, and the Golgi modifies and sorts proteins.
