COMSAE PHASE 1 FORM 114 Actual EXAM – 176
QUESTIONS AND ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED
PASS | LATEST EXAM UPDATE | STUVIA VERIFIED | EXAM
PREP | STUDY GUIDE | PRACTICE TEST
CORE DOMAINS
Osteopathic Principles and Practice (OPP/OMT)
Gross Anatomy and Embryology
Physiology and Pathophysiology
Biochemistry and Molecular Biology
Microbiology and Immunology
Pharmacology and Therapeutics
Pathology
Cardiovascular and Pulmonary Systems
Gastrointestinal and Renal Systems
Neurologic and Behavioral Sciences
Biostatistics, Epidemiology, and Ethics
INTRODUCTION
This comprehensive examination assesses the foundational biomedical
science knowledge and clinical reasoning skills required for COMLEX-USA
Level 1 preparation. It evaluates osteopathic principles, basic science
mechanisms, and integrated clinical application across organ systems. The
examination employs single-best-answer multiple-choice questions with
clinical vignettes to simulate realistic board-style encounters. Emphasis is
placed on mechanism-based reasoning, laboratory interpretation,
osteopathic manipulative medicine, and evidence-based decision-making.
This assessment prepares candidates for the rigor of COMSAE Phase 1
and subsequent COMLEX-USA Level 1 certification.
SECTION ONE: QUESTIONS 1–176
,1. A 24-year-old man develops severe diarrhea after returning from a
camping trip. Laboratory studies show a serum sodium concentration
of 138 mEq/L and a serum osmolality of 290 mOsm/kg. His urine
osmolality is 600 mOsm/kg. Which of the following best explains the
mechanism responsible for maintaining his serum osmolality despite
significant fluid loss?
A. Increased secretion of atrial natriuretic peptide
B. Decreased secretion of antidiuretic hormone
C. Increased renal sodium excretion
D. Increased antidiuretic hormone secretion
D. Increased antidiuretic hormone secretion
RATIONALE: Volume depletion stimulates ADH release, which
increases water reabsorption through aquaporin-2 channels in the
collecting ducts, conserving water and preserving circulating volume even
when serum osmolality is normal.
2. A child presents with recurrent fasting hypoglycemia, lactic
acidosis, hyperuricemia, and hepatomegaly. Laboratory evaluation
reveals impaired conversion of glucose-6-phosphate to free glucose.
Which enzyme is most likely deficient?
A. Lysosomal acid alpha-glucosidase
B. Muscle glycogen phosphorylase
C. Glucose-6-phosphatase
D. Branching enzyme
C. Glucose-6-phosphatase
RATIONALE: Glucose-6-phosphatase deficiency causes von Gierke
disease (glycogen storage disease type I), in which the liver cannot convert
glucose-6-phosphate to free glucose, resulting in severe fasting
hypoglycemia, lactic acidosis, hyperuricemia, and hepatomegaly.
3. A 67-year-old man with chronic obstructive pulmonary disease
develops fever, productive cough, and lobar pneumonia. Sputum
Gram stain reveals gram-positive lancet-shaped diplococci. The
,organism is alpha-hemolytic and optochin sensitive. Which virulence
factor most directly inhibits phagocytosis?
A. Protein A
B. M protein
C. Lipopolysaccharide
D. Polysaccharide capsule
D. Polysaccharide capsule
RATIONALE: Streptococcus pneumoniae is an encapsulated, gram-
positive, lancet-shaped diplococcus that causes community-acquired
pneumonia. Its polysaccharide capsule inhibits phagocytosis and is a major
virulence factor.
4. A patient with hypertension is started on lisinopril. Two weeks later,
he develops persistent dry cough. His serum potassium
concentration has increased slightly. Which mechanism best explains
these findings?
A. Increased aldosterone secretion
B. Increased sympathetic activity
C. Decreased bradykinin degradation
D. Increased renin inhibition
C. Decreased bradykinin degradation
RATIONALE: ACE inhibitors reduce conversion of angiotensin I to
angiotensin II and decrease degradation of bradykinin. Accumulation of
bradykinin can cause a persistent dry cough. Reduced aldosterone
secretion also promotes potassium retention.
5. A researcher is studying a cell that has abundant rough
endoplasmic reticulum and prominent Golgi apparatus. Which
function is most characteristic of this cell?
A. Steroid synthesis
B. Phagocytosis
C. Protein secretion
D. ATP production
, C. Protein secretion
RATIONALE: Cells specialized for protein secretion have extensive
rough endoplasmic reticulum for synthesis of proteins destined for
secretion, followed by processing and packaging in the Golgi apparatus.
6. Which cellular organelle is primarily responsible for oxidative
phosphorylation and generation of most cellular ATP?
A. Lysosome
B. Mitochondrion
C. Peroxisome
D. Golgi apparatus
B. Mitochondrion
RATIONALE: Mitochondria contain the electron transport chain and
ATP synthase in their inner membrane. Oxidative phosphorylation
generates the majority of ATP used by aerobic cells.
7. A mutation prevents a newly synthesized protein from receiving its
normal signal peptide. Which process is most directly impaired?
A. Entry into the nucleus
B. Entry into the rough endoplasmic reticulum
C. Entry into the mitochondrion
D. Degradation by the proteasome
B. Entry into the rough endoplasmic reticulum
RATIONALE: Signal peptides direct many newly synthesized proteins to
the rough endoplasmic reticulum through recognition by signal recognition
particles. Without the signal peptide, secretion or membrane insertion is
disrupted.
8. Which mechanism most directly explains movement of oxygen
across the alveolar-capillary membrane?
A. Primary active transport
B. Facilitated diffusion
QUESTIONS AND ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED
PASS | LATEST EXAM UPDATE | STUVIA VERIFIED | EXAM
PREP | STUDY GUIDE | PRACTICE TEST
CORE DOMAINS
Osteopathic Principles and Practice (OPP/OMT)
Gross Anatomy and Embryology
Physiology and Pathophysiology
Biochemistry and Molecular Biology
Microbiology and Immunology
Pharmacology and Therapeutics
Pathology
Cardiovascular and Pulmonary Systems
Gastrointestinal and Renal Systems
Neurologic and Behavioral Sciences
Biostatistics, Epidemiology, and Ethics
INTRODUCTION
This comprehensive examination assesses the foundational biomedical
science knowledge and clinical reasoning skills required for COMLEX-USA
Level 1 preparation. It evaluates osteopathic principles, basic science
mechanisms, and integrated clinical application across organ systems. The
examination employs single-best-answer multiple-choice questions with
clinical vignettes to simulate realistic board-style encounters. Emphasis is
placed on mechanism-based reasoning, laboratory interpretation,
osteopathic manipulative medicine, and evidence-based decision-making.
This assessment prepares candidates for the rigor of COMSAE Phase 1
and subsequent COMLEX-USA Level 1 certification.
SECTION ONE: QUESTIONS 1–176
,1. A 24-year-old man develops severe diarrhea after returning from a
camping trip. Laboratory studies show a serum sodium concentration
of 138 mEq/L and a serum osmolality of 290 mOsm/kg. His urine
osmolality is 600 mOsm/kg. Which of the following best explains the
mechanism responsible for maintaining his serum osmolality despite
significant fluid loss?
A. Increased secretion of atrial natriuretic peptide
B. Decreased secretion of antidiuretic hormone
C. Increased renal sodium excretion
D. Increased antidiuretic hormone secretion
D. Increased antidiuretic hormone secretion
RATIONALE: Volume depletion stimulates ADH release, which
increases water reabsorption through aquaporin-2 channels in the
collecting ducts, conserving water and preserving circulating volume even
when serum osmolality is normal.
2. A child presents with recurrent fasting hypoglycemia, lactic
acidosis, hyperuricemia, and hepatomegaly. Laboratory evaluation
reveals impaired conversion of glucose-6-phosphate to free glucose.
Which enzyme is most likely deficient?
A. Lysosomal acid alpha-glucosidase
B. Muscle glycogen phosphorylase
C. Glucose-6-phosphatase
D. Branching enzyme
C. Glucose-6-phosphatase
RATIONALE: Glucose-6-phosphatase deficiency causes von Gierke
disease (glycogen storage disease type I), in which the liver cannot convert
glucose-6-phosphate to free glucose, resulting in severe fasting
hypoglycemia, lactic acidosis, hyperuricemia, and hepatomegaly.
3. A 67-year-old man with chronic obstructive pulmonary disease
develops fever, productive cough, and lobar pneumonia. Sputum
Gram stain reveals gram-positive lancet-shaped diplococci. The
,organism is alpha-hemolytic and optochin sensitive. Which virulence
factor most directly inhibits phagocytosis?
A. Protein A
B. M protein
C. Lipopolysaccharide
D. Polysaccharide capsule
D. Polysaccharide capsule
RATIONALE: Streptococcus pneumoniae is an encapsulated, gram-
positive, lancet-shaped diplococcus that causes community-acquired
pneumonia. Its polysaccharide capsule inhibits phagocytosis and is a major
virulence factor.
4. A patient with hypertension is started on lisinopril. Two weeks later,
he develops persistent dry cough. His serum potassium
concentration has increased slightly. Which mechanism best explains
these findings?
A. Increased aldosterone secretion
B. Increased sympathetic activity
C. Decreased bradykinin degradation
D. Increased renin inhibition
C. Decreased bradykinin degradation
RATIONALE: ACE inhibitors reduce conversion of angiotensin I to
angiotensin II and decrease degradation of bradykinin. Accumulation of
bradykinin can cause a persistent dry cough. Reduced aldosterone
secretion also promotes potassium retention.
5. A researcher is studying a cell that has abundant rough
endoplasmic reticulum and prominent Golgi apparatus. Which
function is most characteristic of this cell?
A. Steroid synthesis
B. Phagocytosis
C. Protein secretion
D. ATP production
, C. Protein secretion
RATIONALE: Cells specialized for protein secretion have extensive
rough endoplasmic reticulum for synthesis of proteins destined for
secretion, followed by processing and packaging in the Golgi apparatus.
6. Which cellular organelle is primarily responsible for oxidative
phosphorylation and generation of most cellular ATP?
A. Lysosome
B. Mitochondrion
C. Peroxisome
D. Golgi apparatus
B. Mitochondrion
RATIONALE: Mitochondria contain the electron transport chain and
ATP synthase in their inner membrane. Oxidative phosphorylation
generates the majority of ATP used by aerobic cells.
7. A mutation prevents a newly synthesized protein from receiving its
normal signal peptide. Which process is most directly impaired?
A. Entry into the nucleus
B. Entry into the rough endoplasmic reticulum
C. Entry into the mitochondrion
D. Degradation by the proteasome
B. Entry into the rough endoplasmic reticulum
RATIONALE: Signal peptides direct many newly synthesized proteins to
the rough endoplasmic reticulum through recognition by signal recognition
particles. Without the signal peptide, secretion or membrane insertion is
disrupted.
8. Which mechanism most directly explains movement of oxygen
across the alveolar-capillary membrane?
A. Primary active transport
B. Facilitated diffusion
