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 normally functioning human cell and asks
which structure contains most of the cell's genomic DNA. Which
location is the best answer?
A. Lysosome
B. Nucleus
C. Golgi apparatus
D. Peroxisome
Correct Answer: B. Nucleus
,Rationale: The nucleus contains the cell's chromosomes and therefore
houses most of its genomic DNA. Lysosomes and peroxisomes contain
enzymes, while the Golgi apparatus modifies and sorts proteins.
Although mitochondria contain a small amount of their own DNA, most
cellular genetic information is nuclear.
Question 2
Which cellular organelle is primarily responsible for synthesizing
proteins destined for secretion or insertion into cellular membranes?
A. Free ribosomes
B. Smooth endoplasmic reticulum
C. Rough endoplasmic reticulum
D. Lysosomes
Correct Answer: C. Rough endoplasmic reticulum
Rationale: Ribosomes attached to the rough endoplasmic reticulum
synthesize proteins that enter the secretory pathway, including secreted
proteins and many membrane proteins. Free ribosomes mainly produce
proteins that function within the cytosol or certain organelles. Smooth
endoplasmic reticulum is more closely associated with lipid synthesis
and other specialized metabolic functions, whereas lysosomes digest
intracellular material.
Question 3
A cell contains damaged proteins that must be selectively recognized
and degraded to maintain normal function. Which system is most
directly involved in this process?
A. Ubiquitin-proteasome system
B. Golgi apparatus
, C. Nucleolus
D. Plasma membrane
Correct Answer: A. Ubiquitin-proteasome system
Rationale: The ubiquitin-proteasome system identifies many damaged
or short-lived intracellular proteins for degradation. Proteins marked
with ubiquitin are directed to proteasomes, where they are broken
down into smaller peptides. The Golgi modifies and sorts proteins, the
nucleolus participates in ribosome production, and the plasma
membrane regulates exchange with the extracellular environment.
Question 4
Which cellular process directly produces most adenosine triphosphate
(ATP) under normal aerobic conditions?
A. Glycolysis in the nucleus
B. Oxidative phosphorylation in mitochondria
C. Protein degradation in lysosomes
D. DNA replication in the cytoplasm
Correct Answer: B. Oxidative phosphorylation in mitochondria
Rationale: Under aerobic conditions, mitochondria generate most
cellular ATP through oxidative phosphorylation. Electrons from reduced
metabolic intermediates pass through the electron transport chain,
creating a proton gradient that drives ATP synthesis. Glycolysis occurs in
the cytosol and contributes ATP but does not account for most ATP
production in an aerobically functioning cell.
Question 5
A cell receives an external signal that causes it to change its functional
activity without immediately changing its size or number. This response
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 normally functioning human cell and asks
which structure contains most of the cell's genomic DNA. Which
location is the best answer?
A. Lysosome
B. Nucleus
C. Golgi apparatus
D. Peroxisome
Correct Answer: B. Nucleus
,Rationale: The nucleus contains the cell's chromosomes and therefore
houses most of its genomic DNA. Lysosomes and peroxisomes contain
enzymes, while the Golgi apparatus modifies and sorts proteins.
Although mitochondria contain a small amount of their own DNA, most
cellular genetic information is nuclear.
Question 2
Which cellular organelle is primarily responsible for synthesizing
proteins destined for secretion or insertion into cellular membranes?
A. Free ribosomes
B. Smooth endoplasmic reticulum
C. Rough endoplasmic reticulum
D. Lysosomes
Correct Answer: C. Rough endoplasmic reticulum
Rationale: Ribosomes attached to the rough endoplasmic reticulum
synthesize proteins that enter the secretory pathway, including secreted
proteins and many membrane proteins. Free ribosomes mainly produce
proteins that function within the cytosol or certain organelles. Smooth
endoplasmic reticulum is more closely associated with lipid synthesis
and other specialized metabolic functions, whereas lysosomes digest
intracellular material.
Question 3
A cell contains damaged proteins that must be selectively recognized
and degraded to maintain normal function. Which system is most
directly involved in this process?
A. Ubiquitin-proteasome system
B. Golgi apparatus
, C. Nucleolus
D. Plasma membrane
Correct Answer: A. Ubiquitin-proteasome system
Rationale: The ubiquitin-proteasome system identifies many damaged
or short-lived intracellular proteins for degradation. Proteins marked
with ubiquitin are directed to proteasomes, where they are broken
down into smaller peptides. The Golgi modifies and sorts proteins, the
nucleolus participates in ribosome production, and the plasma
membrane regulates exchange with the extracellular environment.
Question 4
Which cellular process directly produces most adenosine triphosphate
(ATP) under normal aerobic conditions?
A. Glycolysis in the nucleus
B. Oxidative phosphorylation in mitochondria
C. Protein degradation in lysosomes
D. DNA replication in the cytoplasm
Correct Answer: B. Oxidative phosphorylation in mitochondria
Rationale: Under aerobic conditions, mitochondria generate most
cellular ATP through oxidative phosphorylation. Electrons from reduced
metabolic intermediates pass through the electron transport chain,
creating a proton gradient that drives ATP synthesis. Glycolysis occurs in
the cytosol and contributes ATP but does not account for most ATP
production in an aerobically functioning cell.
Question 5
A cell receives an external signal that causes it to change its functional
activity without immediately changing its size or number. This response
