USMLE Step 1 Exam 2026 | High-Yield Medical Sciences
Review Questions
1. Cardiovascular Physiology (Very High Yield)
A 58-year-old man with long-standing hypertension develops left ventricular hypertrophy.
Which change is most responsible for increased afterload?
A. Decreased preload
B. Increased systemic vascular resistance
C. Decreased heart rate
D. Increased venous return
Answer: B. Increased systemic vascular resistance
Explanation: Afterload is the resistance the heart pumps against. In hypertension, systemic
vascular resistance increases, raising afterload and leading to LV hypertrophy.
2. Microbiology (Gram-positive cocci)
A patient presents with skin abscesses. Gram stain shows gram-positive cocci in clusters. The
organism is catalase-positive and coagulase-positive.
Which organism is most likely?
A. Streptococcus pyogenes
B. Staphylococcus epidermidis
C. Staphylococcus aureus
D. Enterococcus faecalis
Answer: C. Staphylococcus aureus
Key point:
Catalase +, coagulase + → S. Aureus
Causes abscesses, pneumonia, endocarditis
3. Pharmacology (Autonomic Drugs)
A patient takes a drug that blocks β1 receptors. What is the most likely effect?
A. Increased heart rate
B. Decreased renin release
,C. Bronchodilation
D. Increased contractility
Answer: B. Decreased renin release
Explanation: β1 receptors in the kidney stimulate renin secretion. Blocking them → ↓ renin
→ ↓ RAAS activity → ↓ BP.
4. Biochemistry (Metabolism)
A patient with alcoholism has confusion, ataxia, and ophthalmoplegia. Which vitamin
deficiency is responsible?
A. Vitamin B6
B. Vitamin B1
C. Vitamin B12
D. Vitamin C
Answer: B. Vitamin B1 (Thiamine)
Key point: Wernicke encephalopathy = B1 deficiency → impaired glucose metabolism in
brain.
5. Microbiology (Viruses)
A child presents with fever, cough, and a “slapped cheek” rash. Which virus is responsible?
A. Rubella virus
B. Parvovirus B19
C. Measles virus
D. EBV
Answer: B. Parvovirus B19
Key point: causes erythema infectiosum (fifth disease) and can cause aplastic crisis.
🫁 6. Respiratory Physiology
A patient with COPD has chronic CO₂ retention. What is the primary renal compensation?
A. Decreased bicarbonate reabsorption
B. Increased bicarbonate retention
C. Increased sodium excretion
, D. Decreased hydrogen secretion
Answer: B. Increased bicarbonate retention
Explanation: Kidneys compensate respiratory acidosis by increasing HCO₃⁻ reabsorption.
7. Neuroanatomy (High Yield Stroke)
A patient has right-sided weakness and expressive aphasia. Where is the lesion?
A. Right temporal lobe
B. Left frontal lobe (Broca area)
C. Cerebellum
D. Occipital lobe
Answer: B. Left frontal lobe (Broca area)
Key point: Language centers are usually in the dominant (left) hemisphere.
8. Renal Physiology
Which segment of the nephron is impermeable to water but reabsorbs Na⁺ and Cl⁻?
A. Proximal tubule
B. Thin descending loop
C. Thick ascending loop
D. Collecting duct
Answer: C. Thick ascending loop
Key point: “Diluting segment” → no water reabsorption, active Na⁺/K⁺/Cl⁻ transport.
9. Inflammation/Pathology
A granuloma with caseating necrosis is most associated with:
A. Staphylococcus aureus
B. Mycobacterium tuberculosis
C. Streptococcus pneumoniae
D. Candida albicans
Answer: B. Mycobacterium tuberculosis
Key point: Caseating granulomas = TB (classic Step 1 pathology)
Review Questions
1. Cardiovascular Physiology (Very High Yield)
A 58-year-old man with long-standing hypertension develops left ventricular hypertrophy.
Which change is most responsible for increased afterload?
A. Decreased preload
B. Increased systemic vascular resistance
C. Decreased heart rate
D. Increased venous return
Answer: B. Increased systemic vascular resistance
Explanation: Afterload is the resistance the heart pumps against. In hypertension, systemic
vascular resistance increases, raising afterload and leading to LV hypertrophy.
2. Microbiology (Gram-positive cocci)
A patient presents with skin abscesses. Gram stain shows gram-positive cocci in clusters. The
organism is catalase-positive and coagulase-positive.
Which organism is most likely?
A. Streptococcus pyogenes
B. Staphylococcus epidermidis
C. Staphylococcus aureus
D. Enterococcus faecalis
Answer: C. Staphylococcus aureus
Key point:
Catalase +, coagulase + → S. Aureus
Causes abscesses, pneumonia, endocarditis
3. Pharmacology (Autonomic Drugs)
A patient takes a drug that blocks β1 receptors. What is the most likely effect?
A. Increased heart rate
B. Decreased renin release
,C. Bronchodilation
D. Increased contractility
Answer: B. Decreased renin release
Explanation: β1 receptors in the kidney stimulate renin secretion. Blocking them → ↓ renin
→ ↓ RAAS activity → ↓ BP.
4. Biochemistry (Metabolism)
A patient with alcoholism has confusion, ataxia, and ophthalmoplegia. Which vitamin
deficiency is responsible?
A. Vitamin B6
B. Vitamin B1
C. Vitamin B12
D. Vitamin C
Answer: B. Vitamin B1 (Thiamine)
Key point: Wernicke encephalopathy = B1 deficiency → impaired glucose metabolism in
brain.
5. Microbiology (Viruses)
A child presents with fever, cough, and a “slapped cheek” rash. Which virus is responsible?
A. Rubella virus
B. Parvovirus B19
C. Measles virus
D. EBV
Answer: B. Parvovirus B19
Key point: causes erythema infectiosum (fifth disease) and can cause aplastic crisis.
🫁 6. Respiratory Physiology
A patient with COPD has chronic CO₂ retention. What is the primary renal compensation?
A. Decreased bicarbonate reabsorption
B. Increased bicarbonate retention
C. Increased sodium excretion
, D. Decreased hydrogen secretion
Answer: B. Increased bicarbonate retention
Explanation: Kidneys compensate respiratory acidosis by increasing HCO₃⁻ reabsorption.
7. Neuroanatomy (High Yield Stroke)
A patient has right-sided weakness and expressive aphasia. Where is the lesion?
A. Right temporal lobe
B. Left frontal lobe (Broca area)
C. Cerebellum
D. Occipital lobe
Answer: B. Left frontal lobe (Broca area)
Key point: Language centers are usually in the dominant (left) hemisphere.
8. Renal Physiology
Which segment of the nephron is impermeable to water but reabsorbs Na⁺ and Cl⁻?
A. Proximal tubule
B. Thin descending loop
C. Thick ascending loop
D. Collecting duct
Answer: C. Thick ascending loop
Key point: “Diluting segment” → no water reabsorption, active Na⁺/K⁺/Cl⁻ transport.
9. Inflammation/Pathology
A granuloma with caseating necrosis is most associated with:
A. Staphylococcus aureus
B. Mycobacterium tuberculosis
C. Streptococcus pneumoniae
D. Candida albicans
Answer: B. Mycobacterium tuberculosis
Key point: Caseating granulomas = TB (classic Step 1 pathology)
