USMLE Step 1 practice questions are for the reasoning you will do on a long day, not for a pile of trivia. The exam is reported pass or fail. The day itself is still a stamina and judgment problem: many short blocks, a shared pool of break time, and items that jump from biochemistry to ethics without announcing the chapter. A useful question bank copies that jump, then teaches the objective after you commit to an answer.
What the day is actually like
StepLobe’s test-day mode follows the Step 1 format used since May 2026: 14 blocks of 20 questions, 30 minutes each. When a block closes, you do not go back to it. Break time is a shared pool of at least 55 minutes across the day, plus an optional 5-minute tutorial. Skip the tutorial and that time joins the breaks. Rehearsing that shape once, on a quiet day, tells you more about your pacing than another untimed evening of single items.
You do not need to open with a full 14-block day. Early on, a single 20-question block at 90 seconds each is enough to feel the clock. Later, string two or three blocks with a short break so you practice the restart, which is where most people lose the first question of the next block. A full test-day mode run is a late tool: one complete 14-by-20 day before the real exam, after you already know how you review. The pass guarantee asks for that one full run, plus six weekly exams, only if you are on an eligible plan and you started early enough.
Subject blocks, then mixed blocks
Start a new system with a tutor block from that system. Tutor mode shows the explanation as you go, which is the right mode while the pathway is still shaky. The job of that block is coverage: can you recognize the objective when the stem is kind enough to stay inside one organ system?
Move to mixed blocks as soon as you can finish a system block without guessing every third item. Mixed is the real skill. The forearm-exercise sample on this page looks like a muscle story and is a glycogen-pathway question. The septic-shock sample looks like a urinary infection and is a receptor question. If you only ever see those items inside a “biochemistry” or “immunology” folder, you are practicing the folder, not the exam. On StepLobe you can build custom blocks, timed or tutor, and you can also run the NBME-style practice exam as 4 blocks of 50. The NBME-style questions page is about the anatomy of a single item. This page is about where that item sits in a week.
How a question and a flashcard share one fact
StepLobe has 33,914 flashcards, one fact each: a context cue, a plain answer, and a reason. A question is a worse flashcard and a better test. Keep them in that relationship. After a block, the only cards you add are objectives you could not say. “Little lactate rise, normal ammonia rise, after ischemic exercise” is a card. The patient’s sport and the color of the urine are the vignette’s clothing, and they do not belong on the card.
Do the due cards before the new block. Questions feel harder, and more honest, when the one-fact layer is already warm. If you are missing items because you never learned the pathway, another 40 questions will not fix it. Go back to the deck or the study pack for that system, then return for a short tutor set. If you are missing items you “knew” as isolated facts, you need more mixed questions, not more rereading.
An error log that stays small
Keep a log you will reread. Three columns are enough: the task the lead-in asked, the reason you picked the distractor, and the objective in one sentence. Group the log by the kind of miss, not by a growing list of disease names.
- Read the stem as a diagnosis and ignored a second-order lead-in.
- Knew the pathway and applied it to the wrong time point, tissue, or direction of change.
- Changed a right answer in the last five seconds because another option sounded familiar.
- Ran out of time and bubbled a letter you had not compared.
The pupil sample is a good check of the second kind of miss. Compression of the oculomotor nerve and ischemia of that nerve both exist. The split is which fibers fail, and the stem gives you the split: a fixed dilated pupil with a complete motor palsy and a thunderclap headache, versus the pupil-sparing pattern you might have memorized from a different patient. If your log says “CN III,” it is too coarse to help tomorrow. If it says “surface parasympathetic fibers fail first under compression,” you can use it.
When to start questions
Start questions while you are still learning the system, not after a mythical day when the book is finished. You need enough of the normal pathway to understand an explanation. You do not need to have “mastered” the system. A useful test is local: can you explain, without notes, what the normal lab or the normal reflex does? If yes, a 10-question tutor set will teach faster than another passive chapter. If no, do the cards and one study pack, then the set.
Protect the last weeks for mixed timed work, weekly exams, and one test-day rehearsal. New resources opened in the final fortnight rarely change a result. They mostly steal review time. If a friend hands you a new file then, the disciplined move is to leave it closed.
What StepLobe’s questions include
The USMLE-style bank in the StepLobe set currently has 2,984 original questions with full explanations, including why each other option fails. The NBME-style bank has 3,494 original questions in the vignette format described on the NBME-style page. Both banks can be used as tutor blocks or timed blocks. Test-day mode runs the 14-by-20 day. Missed questions return after 1, 3, 7, and 21 days. Mark, strikeout, highlight, lab values, a calculator, and notes are on the block screen.
Free, with an account and no card: 10 questions from each bank, 50 flashcards, 2 study packs, week 1 of the plan, and one 50-question sample exam in either style. The free sample exam is the right first timed block if you have never used the interface. Prices for everything else are in the pricing section. The free questions guide explains how to spend that sample so the score report becomes a study list.
These are original questions for study. StepLobe is not affiliated with or endorsed by NBME, FSMB, or USMLE. A score on a StepLobe block is an estimate. It is not an official Step 1 result, and nothing on this page is medical advice.
One week of practice, written out
- Day 1. Due flashcards, then a 20-question tutor block in your weakest system. Write objectives only for misses.
- Day 2. Due cards, then the same system timed, 20 questions, 30 minutes. Review before you close the laptop.
- Day 3. A visual study pack or a deck section for the objective you wrote twice. No new questions.
- Day 4. Mixed tutor block, 20 questions, across at least four systems.
- Day 5. Mixed timed block. Log the kind of miss, using the four types above.
- Day 6. Only the log and the due cards. Re-answer the marked questions without looking at your old letter.
- Day 7. Off, or a single 10-question set if you are restless. Do not start a new resource.
Put that week on the study plan so the hours match your real calendar. The four samples below are a mixed set you can do before Day 1: biochemistry, immunology, neuro-ophthalmology, and reproductive physiology. Choose a letter before you read the box under the options.
Four free USMLE Step 1 questions
These items are original StepLobe questions, printed in full. Nothing is hidden behind a login or a click. Read the vignette in time order, answer the lead-in, then use the explanation, every option, and the educational objective.
Free sample 1 · Biochemistry
Original biochemistry vignette
A 16-year-old girl is brought to the emergency department 5 hours after a weight-training session because of dark brown urine. Since the age of 11 years, she has had painful cramping of her thigh muscles within the first few minutes of sprinting or running up stairs. If she slows to a brisk walk when the cramping begins and keeps going, the cramping subsides after about 10 minutes, and she can then continue at that pace for an hour without symptoms. Today she kept lifting heavy weights despite forearm pain, and her forearm muscles became hard and painful. She has had no symptoms after fasting or during febrile illnesses. Her temperature is 37.0°C (98.6°F), pulse is 84/min, respirations are 14/min, and blood pressure is 118/72 mm Hg. Physical examination shows firm, tender forearm flexor muscles bilaterally. The eyelids and extraocular movements are normal. Muscle strength is 5/5 in the lower extremities. Laboratory studies show:
| Test | Value |
|---|---|
| Serum creatine kinase | 21,000 U/L |
| Serum potassium | 4.6 mEq/L |
| Serum creatinine | 0.8 mg/dL |
| Urine blood (dipstick) | 3+ |
| Urine RBCs | 0–2/hpf |
After she recovers, a forearm exercise test is done, with venous blood drawn before and after repeated maximal handgrip contractions.
Compared with baseline values, which of the following changes in venous lactate and ammonia concentrations after exercise is most likely in this patient?
- A.Excessive rise in lactate and normal rise in ammonia
- B.Little rise in lactate and little rise in ammonia
- C.Little rise in lactate and normal rise in ammonia
- D.Normal rise in lactate and little rise in ammonia
- E.Normal rise in lactate and normal rise in ammonia
Correct answer: C
Myophosphorylase deficiency blocks muscle glycogenolysis, so intense exercise produces little lactate. Adenylate kinase still regenerates ATP, and AMP deaminase converts the resulting AMP to IMP plus NH3, so ammonia rises normally.
Myophosphorylase removes glucose residues from glycogen as glucose-1-phosphate, which then enters glycolysis. During maximal handgrip, muscle depends on this glycogen-derived glycolysis, so venous lactate normally rises 3- to 5-fold. In McArdle disease that flux is absent, and lactate stays flat. ATP demand is partly met by adenylate kinase (2 ADP → ATP + AMP). AMP deaminase then converts AMP to IMP and NH3, which keeps the energy charge from collapsing and raises venous ammonia. When ATP falls far enough, ion pumps and Ca2+ reuptake fail. The result is contracture, sarcolemmal breakdown, CK release and myoglobinuria, as in this patient.
Why each option is right or wrong
- A. An excessive lactate rise means glycolysis is intact but oxidative phosphorylation is impaired, so pyruvate is diverted to lactate. Her block is upstream of glycolysis.
- B. A flat curve for both metabolites means the muscle did not work hard enough. Her intact purine nucleotide pathway should still raise ammonia.
- C. Correct. Blocked glycogenolysis prevents lactate production, while the adenylate kinase and AMP deaminase pathway still generates ammonia.
- D. This reverses the pattern. Glycolysis is intact, but AMP cannot be deaminated. In her disorder, AMP deaminase works and glycogen breakdown does not.
- E. A normal test fits a defect outside glycogen use. Her early cramps, second wind and absent fasting triggers point to a glycogenolysis block.
Educational objective. In myophosphorylase deficiency, forearm exercise produces little lactate rise but a normal ammonia rise because glycogenolysis is blocked while the purine nucleotide pathway is intact.
Free sample 2 · Immunology
Original immunology vignette
A 78-year-old woman is brought to the emergency department from her assisted-living facility because of a 1-day history of fever and confusion. Staff report that she has had urinary frequency and burning with urination for 3 days. She has had no diarrhea. She has type 2 diabetes mellitus. Current medications include metformin. Her temperature is 39.2°C (102.6°F), pulse is 118/min, respirations are 24/min, and blood pressure is 82/46 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 95%. She is oriented to person only. Her skin is warm and flushed, and capillary refill is brisk. There is tenderness to percussion over the right costovertebral angle. The lungs are clear to auscultation. Laboratory studies show:
| Test | Value |
|---|---|
| Hemoglobin | 12.8 g/dL |
| Leukocyte count | 18,600/mm3 |
| Segmented neutrophils | 76% |
| Bands | 14% |
| Platelet count | 108,000/mm3 |
| Creatinine | 1.9 mg/dL |
| Lactate | 4.4 mmol/L (N=0.5–2.2) |
| Urine leukocyte esterase | Positive |
| Urine nitrite | Positive |
A Gram stain of the urine shows neutrophils and gram-negative rods. Blood cultures grow lactose-fermenting gram-negative rods. Her blood pressure remains 84/48 mm Hg after intravenous administration of 30 mL/kg of crystalloid.
Which of the following is the most likely initial molecular event in the host response that led to this patient's hypotension?
- A.ADP-ribosylation of a Gs protein α subunit by a secreted toxin
- B.Flagellin binding to TLR5 on uroepithelial cells
- C.Lipid A binding to CD14 and TLR4–MD-2 on macrophages
- D.Lipoteichoic acid binding to TLR2 on macrophages
- E.Removal of an adenine from 28S rRNA by a Shiga-like toxin
Correct answer: C
Lipid A of Escherichia coli lipopolysaccharide binds CD14 and the TLR4–MD-2 complex on macrophages. NF-κB is activated and TNF-α and IL-1 are released. These cytokines drive nitric oxide–mediated vasodilation and septic shock.
Lipid A is the conserved, toxic core of lipopolysaccharide in the E. coli outer membrane. In plasma, LPS-binding protein transfers LPS to CD14 on monocytes and macrophages, and CD14 delivers it to the TLR4–MD-2 complex. TLR4 signals through MyD88 to activate IκB kinase. IκB is degraded, and NF-κB enters the nucleus to induce TNF-α, pro-IL-1β and IL-6. TNF-α and IL-1 induce inducible nitric oxide synthase, and excess NO lowers systemic vascular resistance, producing this patient's warm, fluid-refractory hypotension. The same cytokines increase capillary permeability and induce tissue factor (thrombocytopenia). Together these impair tissue perfusion, which raises lactate.
Why each option is right or wrong
- A. The heat-labile toxin of enterotoxigenic E. coli raises enterocyte cAMP and causes secretory diarrhea, not shock. This patient has a uropathogenic infection and no diarrhea.
- B. E. coli flagellin can activate TLR5 and drive local urothelial inflammation. Systemic cytokine release and vasodilatory shock in gram-negative bacteremia are driven mainly by lipid A–TLR4 signaling.
- C. Correct. LPS from E. coli is recognized through CD14 and TLR4–MD-2. NF-κB–driven TNF-α and IL-1 release causes NO-mediated vasodilation and septic shock.
- D. Lipoteichoic acid is a cell-wall component of gram-positive bacteria and signals through TLR2. Gram-negative rods do not have it.
- E. Shiga-like toxin of enterohemorrhagic E. coli inactivates 60S ribosomes in gut and renal endothelium. Typical uropathogenic strains do not produce it, and this patient has no bloody diarrhea.
Educational objective. Gram-negative septic shock begins when lipid A of LPS binds CD14 and TLR4–MD-2 on macrophages, activating NF-κB and TNF-α and IL-1 release.
Free sample 3 · Ophthalmology
Original ophthalmology vignette
A 54-year-old woman is brought to the emergency department 3 hours after the sudden onset of a severe headache and drooping of her right eyelid. The headache began while she was gardening, reached maximal intensity within 1 minute, and is the worst she has ever had. She has vomited twice. She has had no loss of consciousness, fever or recent trauma. She has hypertension. Current medications include amlodipine. She has smoked one pack of cigarettes daily for 30 years. Her temperature is 37.1°C (98.8°F), pulse is 90/min, respirations are 16/min, and blood pressure is 172/98 mm Hg. She is alert and fully oriented. Neck flexion causes pain. There is complete ptosis of the right eyelid. When the lid is raised, the right eye is deviated downward and laterally and cannot be adducted, elevated or depressed. The right pupil is 7 mm and the left pupil is 3 mm. Light directed into either eye constricts the left pupil but not the right pupil. Visual acuity, facial sensation and corneal reflexes are normal bilaterally. Muscle strength, sensation and deep tendon reflexes are normal in all extremities.
Which of the following is the most likely mechanism of this patient's pupillary abnormality?
- A.Degeneration of postganglionic neurons in the ciliary ganglion
- B.External compression of peripherally located parasympathetic fibers in the oculomotor nerve
- C.Infarction of the Edinger-Westphal nucleus in the dorsal midbrain
- D.Interruption of sympathetic axons in the internal carotid plexus
- E.Ischemia of centrally located fibers in the oculomotor nerve
Correct answer: B
An expanding posterior communicating artery aneurysm presses on the oculomotor nerve from outside. The parasympathetic pupilloconstrictor fibers run on the surface of the nerve, so they fail early and the pupil dilates and stops reacting.
After leaving the ventral midbrain, the oculomotor nerve passes between the posterior cerebral and superior cerebellar arteries. It runs alongside the posterior communicating artery toward the cavernous sinus. Preganglionic parasympathetic axons from the Edinger-Westphal nucleus travel on the superficial, dorsomedial surface of the nerve. They synapse in the ciliary ganglion, whose postganglionic fibers innervate the sphincter pupillae. An aneurysm pressing from outside deforms these surface axons first. The sympathetic dilator acts unopposed, so the pupil dilates and loses its light response. In diabetic or hypertensive microvascular palsy, occlusion of the vasa nervorum infarcts the core of the nerve. The periphery, supplied by pial collaterals, survives, and the pupil is usually spared.
Why each option is right or wrong
- A. Ciliary ganglion degeneration (tonic pupil) dilates the pupil, but it does not explain the ptosis or the paralysis of the medial, superior and inferior recti.
- B. Correct. An aneurysm compresses CN III from outside. The superficial parasympathetic fibers fail first, producing a fixed dilated pupil alongside the complete motor palsy and thunderclap headache.
- C. A nuclear CN III lesion causes bilateral ptosis, because a single midline subnucleus supplies both levators. It also weakens elevation of the opposite eye. Neither finding is present here.
- D. Sympathetic interruption causes mild ptosis with a small pupil that still reacts to light, and eye movements stay full. This pupil is large and fixed.
- E. Microvascular ischemia infarcts the nerve's core and spares the peripheral pupillomotor fibers. The pupil is typically normal, and the pain builds gradually rather than in seconds.
Educational objective. Aneurysmal compression of the oculomotor nerve dilates the pupil early because the parasympathetic pupillomotor fibers lie superficially, whereas microvascular ischemia affects the core and spares the pupil.
Free sample 4 · Reproductive/OB-GYN
Original reproductive/ob-gyn vignette
A 31-year-old man comes to the office with his wife because they have been unable to conceive despite 2 years of regular unprotected intercourse. His wife has regular menstrual cycles and has a child from a previous relationship. He has never had testicular pain or mumps, and he has had no chemotherapy or radiation therapy. He takes no medications and does not use anabolic steroids or illicit drugs. He is 191 cm (6 ft 3 in) tall and weighs 84 kg (185 lb); BMI is 23 kg/m2. His arm span exceeds his height by 8 cm. Physical examination shows sparse facial and axillary hair and bilateral, nontender, rubbery subareolar tissue 3 cm in diameter. Each testis is firm and has a volume of 3 mL. Analysis of two semen samples shows no spermatozoa. Laboratory studies show:
| Test | Value |
|---|---|
| Follicle-stimulating hormone | 52 mIU/mL |
| Luteinizing hormone | 28 mIU/mL |
| Prolactin | 9 ng/mL |
| Testosterone | 340 ng/dL |
| Estradiol | 55 pg/mL (N=10–40) |
Which of the following most likely accounts for the predominant increase in serum follicle-stimulating hormone concentration in this patient?
- A.Decreased androgen receptor signaling in gonadotrophs
- B.Decreased inhibin B secretion by Sertoli cells
- C.Decreased testosterone secretion by Leydig cells
- D.Increased aromatase conversion of testosterone to estradiol
- E.Increased prolactin secretion by lactotrophs
Correct answer: B
His damaged seminiferous tubules have lost Sertoli cells, which secrete inhibin B, the gonadal hormone that selectively suppresses pituitary FSH. Testosterone is in the normal range, so loss of inhibin B explains why FSH rises far more than LH.
The two testicular compartments send separate feedback signals. Sertoli cells in the seminiferous tubules secrete inhibin B in response to FSH and active spermatogenesis. Inhibin B acts directly on gonadotrophs to suppress FSH β-subunit synthesis without affecting LH. Leydig cells secrete testosterone, which inhibits GnRH and LH, partly after conversion to estradiol. In 47,XXY, germ cells are lost from fetal life onward, and at puberty the tubules hyalinize and fibrose. The result is small, firm testes, azoospermia and a steep fall in inhibin B, so FSH rises markedly. The Leydig cells are clumped and hypofunctional, and they keep testosterone low-normal only because LH is driven up modestly.
Why each option is right or wrong
- A. Androgen resistance at the hypothalamus and pituitary raises LH and drives testosterone to high-normal or high levels. Here testosterone is low-normal and the gonadotropin rise is FSH-predominant.
- B. Correct. Tubular hyalinization destroys Sertoli cells. The resulting loss of inhibin B removes the FSH-selective brake, so FSH rises far more than LH.
- C. Testosterone is normal, and its feedback acts mainly on LH. Leydig dysfunction explains the modest LH rise, not the dominant FSH rise.
- D. Increased aromatization does contribute to his high estradiol and gynecomastia. Estradiol suppresses gonadotropins, so it would lower FSH, not raise it.
- E. Prolactin is normal. Hyperprolactinemia inhibits GnRH pulses and would lower both FSH and LH.
Educational objective. Seminiferous tubule dysgenesis in Klinefelter syndrome lowers Sertoli-cell inhibin B, producing an FSH-predominant gonadotropin rise.
For study only. Not medical advice. StepLobe is not affiliated with or endorsed by NBME, FSMB or USMLE.
How these four belong in a mixed block
None of them announces its chapter in the lead-in. The exercise test asks for the direction of two lab changes, which is a pathway question wearing a sports story. The shock item asks for the first molecular event, not the antibiotic. The pupil item asks which fibers fail, not the name of the artery. The hormone item asks why one gonadotropin rose more than the other, which is feedback, not a karyotype recitation. That is the texture of a mixed Step 1 block. When you want the free timed version of that texture, take the 50-question sample. When you want the line-by-line structure of a single stem, use the NBME-style guide.
The sample exam needs a free account and no card. Founding price is $14.99/month or $139/year ($11.58/month). Yearly starts with 3 days free, card required.
Keep going
- NBME-style questionsHow a vignette, a lead-in, and five options are built, with four fully explained samples.
- Free USMLE-style questionsHow to use the no-card sample exam and the printed items without collecting junk sets.
- Step 1 exam format 202614 blocks of 30 minutes, the shared break pool, and what the content outline weights.
- Question guidesWhich page to read first, and how the two banks differ.
- Free sample exam50 questions, USMLE-style or NBME-style, with a score report.
- Weekly examsA timed NBME-style exam each week, for when you want a standing rehearsal.
- Mnemonics bookA retrieval book for the facts that keep slipping: 717 mnemonics in the 2nd edition, each with the mechanism and a real image or diagram.
- PricingMonthly and yearly founding prices for the full banks, cards, and plan.
Questions students ask
How should I use USMLE Step 1 practice questions?
Learn a system with short tutor blocks, then switch to mixed timed blocks. Review the same day: one sentence for the objective, and one clause for each option you did not understand. Add a flashcard only for a new fact. Rehearse the 14-block day late, not on the first week.
What does a Step 1 practice day look like in StepLobe?
Test-day mode is 14 blocks of 20 questions, 30 minutes each, matching the Step 1 format since May 2026. Break time is a shared pool of at least 55 minutes. You can also build shorter custom blocks at about 90 seconds a question, or use tutor mode.
Should questions be by subject or mixed?
Both, in that order. Subject tutor blocks while a pathway is new. Mixed timed blocks once you can get through a subject set without guessing most of it. The real exam does not label the system in the margin.
How do questions fit with the flashcards?
The 33,914 flashcards hold one fact each. Questions test whether you can find that fact inside a vignette. Do due cards before a block. After the block, make a card only if you could not say the educational objective.
How many USMLE-style questions are in StepLobe?
The USMLE-style bank currently includes 2,984 original questions. The NBME-style bank has 3,494. A free account includes 10 questions from each bank and a 50-question sample exam, with no card. StepLobe is not affiliated with or endorsed by NBME, FSMB, or USMLE.
StepLobe is not affiliated with or endorsed by NBME, FSMB or USMLE. “NBME-style” and “USMLE-style” describe the format of original StepLobe questions. For study only. Not medical advice.