NUR 631 ADVANCED PHYSIOLOGY AND
PATHOPHYSIOLOGY
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS 100% VERIFIED BY
EXPERTS. 2026/2027
1. During muscle atrophy, which molecular pathway is primarily responsible for the
degradation of myofibrillar proteins?
A. The caspase-dependent apoptotic pathway
B. The mitochondrial oxidative phosphorylation pathway
C. The ubiquitin-proteasome pathway
D. The lysosomal exocytosis pathway
Answer: C
Conceptual Explanation: Atrophy involves protein degradation primarily through the
ubiquitin-proteasome pathway, where proteins are conjugated to ubiquitin and then
broken down by the proteasome.
,2. Which of the following describes the mechanism of cell injury caused by reactive oxygen
species (ROS)?
A. Stabilization of the cellular membrane
B. Lipid peroxidation and DNA fragmentation
C. Inactivation of protein kinases
D. Enhancement of mitochondrial ATP production
Answer: B
Conceptual Explanation: ROS cause oxidative stress leading to lipid peroxidation of
membranes, protein carbonylation, and DNA damage/fragmentation.
3. In the extrinsic pathway of apoptosis, the binding of Fas ligand to its receptor leads to the
activation of which initiator caspase?
A. Caspase-3
B. Caspase-8
C. Caspase-9
D. Caspase-1
Answer: B
Conceptual Explanation: Caspase-8 is the primary initiator caspase for the extrinsic
(death receptor-mediated) apoptotic pathway.
, 4. Which epigenetic modification typically results in the silencing of gene expression?
A. Histone acetylation
B. RNA interference by mRNA
C. DNA methylation at CpG islands
D. Demethylation of promoter regions
Answer: C
Conceptual Explanation: DNA methylation, particularly at CpG islands in promoter
regions, generally inhibits gene transcription, leading to gene silencing.
5. What is the primary effect of hyperkalemia on the resting membrane potential (RMP) of a
neuron?
A. It hyperpolarizes the RMP, making it more negative
B. It depolarizes the RMP, making it less negative
C. It has no effect on the RMP
D. It increases the threshold for an action potential
Answer: B
Conceptual Explanation: Increased extracellular potassium reduces the concentration
gradient, leading to less K+ efflux and a more positive (depolarized) resting membrane
potential.
PATHOPHYSIOLOGY
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS 100% VERIFIED BY
EXPERTS. 2026/2027
1. During muscle atrophy, which molecular pathway is primarily responsible for the
degradation of myofibrillar proteins?
A. The caspase-dependent apoptotic pathway
B. The mitochondrial oxidative phosphorylation pathway
C. The ubiquitin-proteasome pathway
D. The lysosomal exocytosis pathway
Answer: C
Conceptual Explanation: Atrophy involves protein degradation primarily through the
ubiquitin-proteasome pathway, where proteins are conjugated to ubiquitin and then
broken down by the proteasome.
,2. Which of the following describes the mechanism of cell injury caused by reactive oxygen
species (ROS)?
A. Stabilization of the cellular membrane
B. Lipid peroxidation and DNA fragmentation
C. Inactivation of protein kinases
D. Enhancement of mitochondrial ATP production
Answer: B
Conceptual Explanation: ROS cause oxidative stress leading to lipid peroxidation of
membranes, protein carbonylation, and DNA damage/fragmentation.
3. In the extrinsic pathway of apoptosis, the binding of Fas ligand to its receptor leads to the
activation of which initiator caspase?
A. Caspase-3
B. Caspase-8
C. Caspase-9
D. Caspase-1
Answer: B
Conceptual Explanation: Caspase-8 is the primary initiator caspase for the extrinsic
(death receptor-mediated) apoptotic pathway.
, 4. Which epigenetic modification typically results in the silencing of gene expression?
A. Histone acetylation
B. RNA interference by mRNA
C. DNA methylation at CpG islands
D. Demethylation of promoter regions
Answer: C
Conceptual Explanation: DNA methylation, particularly at CpG islands in promoter
regions, generally inhibits gene transcription, leading to gene silencing.
5. What is the primary effect of hyperkalemia on the resting membrane potential (RMP) of a
neuron?
A. It hyperpolarizes the RMP, making it more negative
B. It depolarizes the RMP, making it less negative
C. It has no effect on the RMP
D. It increases the threshold for an action potential
Answer: B
Conceptual Explanation: Increased extracellular potassium reduces the concentration
gradient, leading to less K+ efflux and a more positive (depolarized) resting membrane
potential.
