COMSAE PHASE 1 FORM 110I EXAM PRACTICE | COMPREHENSIVE STUDY GUIDE |
ADVANCED TESTBANK WITH PRACTICE QUESTIONS & ANSWERS | EXAM
PREPARATION | LATEST UPDATE 2026/2027
TABLE OF CONTENTS
i. Biochemistry, Molecular Biology & Genetics
ii. Microbiology, Immunology & Infectious Disease
iii. Physiology & Pathophysiology
iv. Pharmacology & Therapeutics
v. Anatomy, Embryology & Histology
vi. Behavioral Science, Ethics & Epidemiology
vii. Integrated Clinical Reasoning & Multisystem Disease
INTRODUCTION
This comprehensive COMSAE Phase 1 Form 110i practice set is designed as an
original study resource for students preparing for foundational osteopathic medical
licensing examinations. It emphasizes integration of biomedical sciences with
clinical reasoning rather than isolated factual recall. Questions span molecular
mechanisms, anatomy, physiology, pathology, microbiology, immunology,
pharmacology, behavioral science, epidemiology, and osteopathic-relevant clinical
concepts. The difficulty ranges from advanced to highly challenging, with emphasis
on mechanism-based reasoning, interpretation of laboratory and clinical findings,
pharmacologic consequences, and distinguishing closely related diagnoses.
Students should expect realistic vignettes requiring identification of the underlying
process, prediction of physiologic consequences, and selection of the most
appropriate answer from plausible alternatives.
Question 1
A 24-year-old man develops severe muscle cramping and dark urine after
beginning an intense exercise program. Laboratory studies show markedly elevated
creatine kinase and lactate. His symptoms improve after several minutes of rest.
Genetic testing reveals a deficiency of myophosphorylase. Which metabolic
abnormality most directly explains his inability to sustain strenuous exercise?
,A. Impaired conversion of pyruvate to acetyl-CoA
B. Impaired breakdown of muscle glycogen
C. Impaired fatty-acid transport into mitochondria
D. Impaired oxidative phosphorylation
🔴 Correct Answer: B. Impaired breakdown of muscle glycogen.
🔵 Explanation: Myophosphorylase catalyzes glycogenolysis in skeletal muscle.
Deficiency causes McArdle disease, producing exercise intolerance, muscle cramps,
rhabdomyolysis, and an inadequate rise in lactate during strenuous exercise. Muscle
cannot efficiently mobilize glycogen to generate glucose-6-phosphate for glycolysis.
Question 2
A newborn develops profound hypoglycemia, lactic acidosis, hyperuricemia, and
hepatomegaly shortly after beginning feeds. Laboratory testing demonstrates
accumulation of glucose-6-phosphate in hepatocytes. Which additional finding is
most likely?
A. Increased hepatic glycogen storage
B. Decreased triglyceride synthesis
C. Increased ketone utilization by skeletal muscle
D. Decreased production of uric acid
🔴 Correct Answer: A. Increased hepatic glycogen storage.
🔵 Explanation: Glucose-6-phosphatase deficiency causes von Gierke disease.
Glucose-6-phosphate cannot be converted into free glucose, causing severe fasting
hypoglycemia and accumulation of glycogen and metabolic intermediates.
Hyperuricemia and lactic acidosis are characteristic associated findings.
Question 3
A 6-year-old child has recurrent sinopulmonary infections caused by encapsulated
bacteria. Laboratory testing demonstrates absent mature B cells and markedly
decreased immunoglobulin concentrations. Which molecular defect most likely
accounts for this condition?
A. Defective CD40 ligand expression
B. Defective Bruton's tyrosine kinase activity
,C. Defective NADPH oxidase activity
D. Defective adenosine deaminase activity
🔴 Correct Answer: B. Defective Bruton's tyrosine kinase activity.
🔵 Explanation: X-linked agammaglobulinemia results from defective Bruton's
tyrosine kinase, preventing maturation of B-cell precursors into mature B
lymphocytes. Patients develop recurrent bacterial infections after maternal IgG wanes.
Question 4
A 32-year-old woman presents with fatigue, weight loss, diarrhea, and abdominal
pain. Colonoscopy reveals continuous inflammation beginning at the rectum and
extending proximally. Histology demonstrates crypt abscesses. Which complication
is particularly associated with this disease?
A. Toxic megacolon
B. Transmural fistula formation
C. Calcium oxalate nephrolithiasis
D. Vitamin B12 deficiency due to ileal disease
🔴 Correct Answer: A. Toxic megacolon.
🔵 Explanation: Ulcerative colitis causes continuous mucosal inflammation beginning
in the rectum. Severe disease can produce toxic megacolon, a potentially life-
threatening complication characterized by colonic dilation and systemic toxicity.
Transmural fistulas and strictures are more characteristic of Crohn disease.
Question 5
A 58-year-old man with hypertension develops a persistent dry cough several
weeks after starting a new antihypertensive medication. His renal function and
electrolytes are normal. Which mechanism most directly causes this adverse effect?
A. Increased bradykinin degradation
B. Increased angiotensin II receptor stimulation
C. Decreased degradation of bradykinin
D. Increased aldosterone secretion
, 🔴 Correct Answer: C. Decreased degradation of bradykinin.
🔵 Explanation: Angiotensin-converting enzyme inhibitors decrease formation of
angiotensin II and also reduce degradation of bradykinin. Accumulation of bradykinin
contributes to the characteristic dry cough and can also cause angioedema.
Question 6
A patient with chronic obstructive pulmonary disease has severe airflow
obstruction. Pulmonary function testing demonstrates a reduced FEV1/FVC ratio.
Which change would most directly improve the patient's expiratory airflow?
A. Decreased airway smooth-muscle tone
B. Increased pulmonary capillary hydrostatic pressure
C. Decreased surfactant production
D. Increased pulmonary vascular resistance
🔴 Correct Answer: A. Decreased airway smooth-muscle tone.
🔵 Explanation: Bronchodilation decreases airway resistance and improves expiratory
airflow in obstructive lung disease. β2-adrenergic agonists increase intracellular cAMP
in bronchial smooth muscle, producing relaxation and bronchodilation.
Question 7
A 19-year-old man presents with fever, severe headache, photophobia, and neck
stiffness. Cerebrospinal fluid shows neutrophilic pleocytosis, elevated protein, and
decreased glucose. Gram stain demonstrates gram-negative diplococci. Which
bacterial virulence factor is most important in allowing the organism to evade
phagocytosis?
A. M protein
B. Polysaccharide capsule
C. Protein A
D. Endotoxin-neutralizing exotoxin
🔴 Correct Answer: B. Polysaccharide capsule.
🔵 Explanation: Neisseria meningitidis possesses a polysaccharide capsule that
inhibits phagocytosis and is a major virulence determinant. Its lipooligosaccharide
endotoxin contributes to fever, vascular injury, and septic shock.
ADVANCED TESTBANK WITH PRACTICE QUESTIONS & ANSWERS | EXAM
PREPARATION | LATEST UPDATE 2026/2027
TABLE OF CONTENTS
i. Biochemistry, Molecular Biology & Genetics
ii. Microbiology, Immunology & Infectious Disease
iii. Physiology & Pathophysiology
iv. Pharmacology & Therapeutics
v. Anatomy, Embryology & Histology
vi. Behavioral Science, Ethics & Epidemiology
vii. Integrated Clinical Reasoning & Multisystem Disease
INTRODUCTION
This comprehensive COMSAE Phase 1 Form 110i practice set is designed as an
original study resource for students preparing for foundational osteopathic medical
licensing examinations. It emphasizes integration of biomedical sciences with
clinical reasoning rather than isolated factual recall. Questions span molecular
mechanisms, anatomy, physiology, pathology, microbiology, immunology,
pharmacology, behavioral science, epidemiology, and osteopathic-relevant clinical
concepts. The difficulty ranges from advanced to highly challenging, with emphasis
on mechanism-based reasoning, interpretation of laboratory and clinical findings,
pharmacologic consequences, and distinguishing closely related diagnoses.
Students should expect realistic vignettes requiring identification of the underlying
process, prediction of physiologic consequences, and selection of the most
appropriate answer from plausible alternatives.
Question 1
A 24-year-old man develops severe muscle cramping and dark urine after
beginning an intense exercise program. Laboratory studies show markedly elevated
creatine kinase and lactate. His symptoms improve after several minutes of rest.
Genetic testing reveals a deficiency of myophosphorylase. Which metabolic
abnormality most directly explains his inability to sustain strenuous exercise?
,A. Impaired conversion of pyruvate to acetyl-CoA
B. Impaired breakdown of muscle glycogen
C. Impaired fatty-acid transport into mitochondria
D. Impaired oxidative phosphorylation
🔴 Correct Answer: B. Impaired breakdown of muscle glycogen.
🔵 Explanation: Myophosphorylase catalyzes glycogenolysis in skeletal muscle.
Deficiency causes McArdle disease, producing exercise intolerance, muscle cramps,
rhabdomyolysis, and an inadequate rise in lactate during strenuous exercise. Muscle
cannot efficiently mobilize glycogen to generate glucose-6-phosphate for glycolysis.
Question 2
A newborn develops profound hypoglycemia, lactic acidosis, hyperuricemia, and
hepatomegaly shortly after beginning feeds. Laboratory testing demonstrates
accumulation of glucose-6-phosphate in hepatocytes. Which additional finding is
most likely?
A. Increased hepatic glycogen storage
B. Decreased triglyceride synthesis
C. Increased ketone utilization by skeletal muscle
D. Decreased production of uric acid
🔴 Correct Answer: A. Increased hepatic glycogen storage.
🔵 Explanation: Glucose-6-phosphatase deficiency causes von Gierke disease.
Glucose-6-phosphate cannot be converted into free glucose, causing severe fasting
hypoglycemia and accumulation of glycogen and metabolic intermediates.
Hyperuricemia and lactic acidosis are characteristic associated findings.
Question 3
A 6-year-old child has recurrent sinopulmonary infections caused by encapsulated
bacteria. Laboratory testing demonstrates absent mature B cells and markedly
decreased immunoglobulin concentrations. Which molecular defect most likely
accounts for this condition?
A. Defective CD40 ligand expression
B. Defective Bruton's tyrosine kinase activity
,C. Defective NADPH oxidase activity
D. Defective adenosine deaminase activity
🔴 Correct Answer: B. Defective Bruton's tyrosine kinase activity.
🔵 Explanation: X-linked agammaglobulinemia results from defective Bruton's
tyrosine kinase, preventing maturation of B-cell precursors into mature B
lymphocytes. Patients develop recurrent bacterial infections after maternal IgG wanes.
Question 4
A 32-year-old woman presents with fatigue, weight loss, diarrhea, and abdominal
pain. Colonoscopy reveals continuous inflammation beginning at the rectum and
extending proximally. Histology demonstrates crypt abscesses. Which complication
is particularly associated with this disease?
A. Toxic megacolon
B. Transmural fistula formation
C. Calcium oxalate nephrolithiasis
D. Vitamin B12 deficiency due to ileal disease
🔴 Correct Answer: A. Toxic megacolon.
🔵 Explanation: Ulcerative colitis causes continuous mucosal inflammation beginning
in the rectum. Severe disease can produce toxic megacolon, a potentially life-
threatening complication characterized by colonic dilation and systemic toxicity.
Transmural fistulas and strictures are more characteristic of Crohn disease.
Question 5
A 58-year-old man with hypertension develops a persistent dry cough several
weeks after starting a new antihypertensive medication. His renal function and
electrolytes are normal. Which mechanism most directly causes this adverse effect?
A. Increased bradykinin degradation
B. Increased angiotensin II receptor stimulation
C. Decreased degradation of bradykinin
D. Increased aldosterone secretion
, 🔴 Correct Answer: C. Decreased degradation of bradykinin.
🔵 Explanation: Angiotensin-converting enzyme inhibitors decrease formation of
angiotensin II and also reduce degradation of bradykinin. Accumulation of bradykinin
contributes to the characteristic dry cough and can also cause angioedema.
Question 6
A patient with chronic obstructive pulmonary disease has severe airflow
obstruction. Pulmonary function testing demonstrates a reduced FEV1/FVC ratio.
Which change would most directly improve the patient's expiratory airflow?
A. Decreased airway smooth-muscle tone
B. Increased pulmonary capillary hydrostatic pressure
C. Decreased surfactant production
D. Increased pulmonary vascular resistance
🔴 Correct Answer: A. Decreased airway smooth-muscle tone.
🔵 Explanation: Bronchodilation decreases airway resistance and improves expiratory
airflow in obstructive lung disease. β2-adrenergic agonists increase intracellular cAMP
in bronchial smooth muscle, producing relaxation and bronchodilation.
Question 7
A 19-year-old man presents with fever, severe headache, photophobia, and neck
stiffness. Cerebrospinal fluid shows neutrophilic pleocytosis, elevated protein, and
decreased glucose. Gram stain demonstrates gram-negative diplococci. Which
bacterial virulence factor is most important in allowing the organism to evade
phagocytosis?
A. M protein
B. Polysaccharide capsule
C. Protein A
D. Endotoxin-neutralizing exotoxin
🔴 Correct Answer: B. Polysaccharide capsule.
🔵 Explanation: Neisseria meningitidis possesses a polysaccharide capsule that
inhibits phagocytosis and is a major virulence determinant. Its lipooligosaccharide
endotoxin contributes to fever, vascular injury, and septic shock.
