USMLE Step 1 Exam Guide 2026: FREE Pass/Fail Plan + May 14 Format
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A 45-year-old man presents with fatigue and jaundice. Laboratory studies show elevated unconjugated bilirubin. Which enzyme deficiency is most likely responsible for this presentation?
Usmle General Principles
Question · Easy
P-R-I-L: the -pril arena anthem
Short
Complete 2026 USMLE Step 1 guide. Pass/fail since Jan 2022, $695 fee, format change May 14, 2026 (14 blocks x 30 min x 20 Qs, 55-min break, 5-min tutorial). FREE practice, high-yield content, 6-week dedicated plan.
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Which bilirubin-processing enzyme is deficient in Gilbert syndrome and Crigler-Najjar syndrome?
Biochemistry
Flashcard
A 2-year-old child presents with developmental delay, intellectual disability, and a musty odor to the urine. Which dietary restriction is essential for this patient?
___ score: newborn rating at 1 and 5 minutes after birth in which each of five signs is scored 0, 1 or 2.
Human Development
Guess the Term
Chapter 1: Step 1 Exam Roadmap and Official Sources
1.1 Format, Scoring, Fees, and 2026 Software Change
Study guide
Cheat sheet
A researcher is studying a signaling pathway where a ligand binds to a receptor tyrosine kinase, leading to cell proliferation. Which of the following is the most likely downstream signaling molecule in this pathway?
Question · Medium
Read the clue and guess the term in 6 tries.
Game
What is the enzyme defect and dietary treatment in classic phenylketonuria?
A 6-month-old infant presents with fasting hypoglycemia, hepatomegaly, and lactic acidosis. A liver biopsy shows glycogen accumulation. Which enzyme deficiency is most likely?
Condition in which the blood produces fewer healthy red blood cells than normal, reducing oxygen delivery.
Blood and immune
A patient with a history of alcohol abuse presents with neurological symptoms including ophthalmoplegia, ataxia, and confusion. Which vitamin deficiency is most likely responsible?
Which glycogen storage disease causes severe fasting hypoglycemia, lactic acidosis, hyperuricemia, and hepatomegaly?
A newborn presents with lethargy, vomiting, and jaundice shortly after introducing breast milk. Laboratory studies show elevated galactose and galactitol in the blood. Which enzyme is deficient?
___ cell disease: inherited blood disorder in which hemoglobin forms stiff rods, making red blood cells crescent-shaped and able to block blood flow.
1.2 Eligibility, Results, Retakes, and Source Control
A patient with chronic granulomatous disease develops recurrent infections with catalase-positive organisms. What is the underlying defect in this condition?
Swap tiles to line up three of the same term.
Term Match
Which enzyme is deficient in classic galactosemia?
A cell line is found to have a mutation in the p53 gene. Which cellular process is most likely impaired?
Brain injury caused by a blocked or ruptured blood vessel that requires emergency care.
Brain and behavior
A patient presents with muscle weakness and myoglobinuria after vigorous exercise. Which metabolic pathway is most likely impaired?
Question · Hard
Which vitamin-derived cofactor is required by pyruvate dehydrogenase?
Which enzyme catalyzes the rate-limiting step in cholesterol synthesis?
___ spectrum disorder: condition that affects how a person interacts, communicates, learns, and behaves, with signs usually appearing in the first two years.
Chapter 2: Question Method and Study System
2.1 Single-Best-Answer Vignette Method
A patient with hyperlipidemia is prescribed a medication that inhibits intestinal cholesterol absorption. Which transporter is targeted by this drug?
Flip two cards at a time to find matching terms.
Term Pairs
What is the rate-limiting enzyme in cholesterol synthesis and what drug class targets it?
Pharmacology
In the TCA cycle, which reaction produces GTP through substrate-level phosphorylation?
Chronic autoimmune disease that can affect the skin, joints, kidneys, blood, and brain.
Bones, joints, and skin
A patient with type 2 diabetes has elevated fasting glucose. Which enzyme is most likely showing decreased activity in the liver due to insulin resistance?
What genetic mechanism causes fragile X syndrome?
Genetics
Which of the following is a ketogenic amino acid that can be converted to acetoacetyl-CoA?
Painful arthritis caused by needle-shaped urate crystals forming in a joint, often starting in the big toe.
2.2 Blueprint-Weighted Study System
A patient with hyperammonemia is found to have a urea cycle enzyme deficiency. Which amino acid can be supplemented to provide an alternative pathway for nitrogen disposal?
Find five hidden terms in a grid of letters.
Term Search
How do Prader-Willi and Angelman syndromes differ at chromosome 15q11-q13?
Which cofactor is required for the conversion of pyruvate to acetyl-CoA by the pyruvate dehydrogenase complex?
Chest discomfort that is a common symptom of coronary heart disease and can warn of a higher risk of a heart attack.
Heart and vessels
A child presents with intellectual disability, microcephaly, and a distinctive facial appearance with a long face, large ears, and macroorchidism. What is the genetic mechanism of this disorder?
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