NU 545 UNIT 1 EXAM: CELLULAR BIOLOGY & MECHANISMS
OF SELF-DEFENSE QUESTIONS AND CORRECT ANSWERS
WITH RATIONALE NEW UPDATE 2026-2027 GRADED A+
49 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Differentiate mechanisms of reversible and irreversible cellular injury, including free radical injury, hypoxic
injury, and apoptosis
2 Analyze the cellular and molecular events of acute and chronic inflammation, including mediators,
leukocyte recruitment, and resolution
3 Compare innate and adaptive immunity, including antigen presentation, lymphocyte activation, and
immunodeficiencies
4 Evaluate hematologic and lymphatic disorders using current diagnostic criteria and pathophysiologic
reasoning
5 Apply principles of wound healing, regeneration, and fibrosis to clinical scenarios
6 NU 545 Unit 1 Exam
7 Cellular Biology & Mechanisms of Self
8 Defense Questions and Correct Answers with Rationale New Update 2026
9 2027 Graded A+
10 Foundations of Cellular Biology & Mechanisms of Self-Defense
11 Applied Cellular Biology & Mechanisms of Self-Defense
12 Advanced Cellular Biology & Mechanisms of Self-Defense
13 Cellular Biology & Mechanisms of Self-Defense Review
ABSTRACT
Page 1
,This study document brings together 49 carefully worded exam questions drawn from NU 545 Unit
1 Exam: Cellular Biology & Mechanisms of Self-Defense Questions and Correct Answers with
Rationale New Update 2026-2027 Graded A+, with the strongest emphasis placed on Differentiate
mechanisms of reversible and irreversible cellular injury, including free radical injury, hypoxic injury,
and apoptosis, Analyze the cellular and molecular events of acute and chronic inflammation,
including mediators, leukocyte recruitment, and resolution, Compare innate and adaptive immunity,
including antigen presentation, lymphocyte activation and and immunodeficiencies. Every item
follows the wording style and level of reasoning you meet in the real paper, and each one is paired
with a clear rationale so the correct choice is never a guess. Work through the set at your own
pace, mark the questions that slow you down, then come back to them until the reasoning feels
automatic. Learners who revise this way walk into the exam room recognising the pattern behind
the questions instead of meeting them for the first time. Keep going - steady, honest practice is
what turns a difficult paper into a comfortable pass.
Q1 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
A cell is deprived of oxygen, leading to ATP depletion. Which of the following best
explains why the sodium-potassium ATPase pump fails first, and what immediate
consequence follows?
A. Failure of the pump causes intracellular sodium accumulation, which draws water in and leads
to cellular swelling. CORRECT
B. Failure of the pump causes intracellular potassium accumulation, which draws water out and
leads to cellular shrinkage.
C. Failure of the pump causes calcium influx, which activates proteases and directly lyses the
cell membrane.
D. Failure of the pump causes anaerobic glycolysis to cease, leading to immediate cell death.
RATIONALE: The Na+/K+ ATPase is highly ATP-dependent; when ATP falls, it fails, causing Na+
to accumulate intracellularly, followed by osmotic water influx and swelling (hydropic change).
This is a classic early reversible injury. Options B, C, and D misrepresent ion gradients or timing;
calcium influx occurs later, and anaerobic glycolysis may continue briefly.
Page 2
, Q2 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
During an acute inflammatory response, which sequence of leukocyte-endothelial
interactions correctly describes the transition from rolling to firm adhesion?
A. Selectins mediate rolling, then integrins mediate firm adhesion via ICAM-1 on endothelium.
CORRECT
B. Integrins mediate rolling, then selectins mediate firm adhesion via VCAM-1 on endothelium.
C. PECAM-1 mediates rolling, then selectins mediate firm adhesion via ICAM-1 on endothelium.
D. Selectins mediate firm adhesion, then integrins mediate transmigration via PECAM-1.
RATIONALE: Selectins (L-, P-, E-) mediate initial rolling by binding sialylated ligands; then
chemokines activate integrins (LFA-1, MAC-1) on leukocytes, which bind ICAM-1 on endothelium
for firm adhesion. Transmigration follows via PECAM-1. Options B, C, and D reverse or
misassign these roles.
Q3 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
Which statement best distinguishes apoptosis from necrosis in terms of cellular
content release and inflammatory response?
A. Apoptosis releases cellular contents that trigger inflammation, whereas necrosis is silent.
B. Necrosis is an energy-dependent process that avoids inflammation, whereas apoptosis
causes inflammation.
C. Apoptosis is energy-dependent and avoids inflammation, whereas necrosis releases contents
that trigger inflammation. CORRECT
D. Both apoptosis and necrosis are energy-independent and cause identical inflammatory
responses.
RATIONALE: Apoptosis is a regulated, ATP-dependent process where the cell shrinks and forms
apoptotic bodies that are phagocytosed without inflammation. Necrosis is typically
energy-independent, causing cell swelling, membrane rupture, and release of DAMPs that incite
inflammation. Options A, B, and D incorrectly describe these mechanisms.
Page 3
OF SELF-DEFENSE QUESTIONS AND CORRECT ANSWERS
WITH RATIONALE NEW UPDATE 2026-2027 GRADED A+
49 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Differentiate mechanisms of reversible and irreversible cellular injury, including free radical injury, hypoxic
injury, and apoptosis
2 Analyze the cellular and molecular events of acute and chronic inflammation, including mediators,
leukocyte recruitment, and resolution
3 Compare innate and adaptive immunity, including antigen presentation, lymphocyte activation, and
immunodeficiencies
4 Evaluate hematologic and lymphatic disorders using current diagnostic criteria and pathophysiologic
reasoning
5 Apply principles of wound healing, regeneration, and fibrosis to clinical scenarios
6 NU 545 Unit 1 Exam
7 Cellular Biology & Mechanisms of Self
8 Defense Questions and Correct Answers with Rationale New Update 2026
9 2027 Graded A+
10 Foundations of Cellular Biology & Mechanisms of Self-Defense
11 Applied Cellular Biology & Mechanisms of Self-Defense
12 Advanced Cellular Biology & Mechanisms of Self-Defense
13 Cellular Biology & Mechanisms of Self-Defense Review
ABSTRACT
Page 1
,This study document brings together 49 carefully worded exam questions drawn from NU 545 Unit
1 Exam: Cellular Biology & Mechanisms of Self-Defense Questions and Correct Answers with
Rationale New Update 2026-2027 Graded A+, with the strongest emphasis placed on Differentiate
mechanisms of reversible and irreversible cellular injury, including free radical injury, hypoxic injury,
and apoptosis, Analyze the cellular and molecular events of acute and chronic inflammation,
including mediators, leukocyte recruitment, and resolution, Compare innate and adaptive immunity,
including antigen presentation, lymphocyte activation and and immunodeficiencies. Every item
follows the wording style and level of reasoning you meet in the real paper, and each one is paired
with a clear rationale so the correct choice is never a guess. Work through the set at your own
pace, mark the questions that slow you down, then come back to them until the reasoning feels
automatic. Learners who revise this way walk into the exam room recognising the pattern behind
the questions instead of meeting them for the first time. Keep going - steady, honest practice is
what turns a difficult paper into a comfortable pass.
Q1 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
A cell is deprived of oxygen, leading to ATP depletion. Which of the following best
explains why the sodium-potassium ATPase pump fails first, and what immediate
consequence follows?
A. Failure of the pump causes intracellular sodium accumulation, which draws water in and leads
to cellular swelling. CORRECT
B. Failure of the pump causes intracellular potassium accumulation, which draws water out and
leads to cellular shrinkage.
C. Failure of the pump causes calcium influx, which activates proteases and directly lyses the
cell membrane.
D. Failure of the pump causes anaerobic glycolysis to cease, leading to immediate cell death.
RATIONALE: The Na+/K+ ATPase is highly ATP-dependent; when ATP falls, it fails, causing Na+
to accumulate intracellularly, followed by osmotic water influx and swelling (hydropic change).
This is a classic early reversible injury. Options B, C, and D misrepresent ion gradients or timing;
calcium influx occurs later, and anaerobic glycolysis may continue briefly.
Page 2
, Q2 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
During an acute inflammatory response, which sequence of leukocyte-endothelial
interactions correctly describes the transition from rolling to firm adhesion?
A. Selectins mediate rolling, then integrins mediate firm adhesion via ICAM-1 on endothelium.
CORRECT
B. Integrins mediate rolling, then selectins mediate firm adhesion via VCAM-1 on endothelium.
C. PECAM-1 mediates rolling, then selectins mediate firm adhesion via ICAM-1 on endothelium.
D. Selectins mediate firm adhesion, then integrins mediate transmigration via PECAM-1.
RATIONALE: Selectins (L-, P-, E-) mediate initial rolling by binding sialylated ligands; then
chemokines activate integrins (LFA-1, MAC-1) on leukocytes, which bind ICAM-1 on endothelium
for firm adhesion. Transmigration follows via PECAM-1. Options B, C, and D reverse or
misassign these roles.
Q3 DIFFERENTIATE MECHANISMS OF REVERSIBLE AND IRREVERSIBLE CELLULAR INJURY,
INCLUDING FREE RADICAL INJURY, HYPOXIC INJURY, AND APOPTOSIS
Which statement best distinguishes apoptosis from necrosis in terms of cellular
content release and inflammatory response?
A. Apoptosis releases cellular contents that trigger inflammation, whereas necrosis is silent.
B. Necrosis is an energy-dependent process that avoids inflammation, whereas apoptosis
causes inflammation.
C. Apoptosis is energy-dependent and avoids inflammation, whereas necrosis releases contents
that trigger inflammation. CORRECT
D. Both apoptosis and necrosis are energy-independent and cause identical inflammatory
responses.
RATIONALE: Apoptosis is a regulated, ATP-dependent process where the cell shrinks and forms
apoptotic bodies that are phagocytosed without inflammation. Necrosis is typically
energy-independent, causing cell swelling, membrane rupture, and release of DAMPs that incite
inflammation. Options A, B, and D incorrectly describe these mechanisms.
Page 3
