USMLE STEP 1 EXAM |ACTUAL QUESTIONS AND
VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
A 26 years old asian man comes to the physician because of palpitations, dizzy spells, and
intense weakness. he collapses and loses consciousness. an advanced cardiac life support
protocol is executed. with the underlying rhythm being ventricular fibrillation, a series of
electrical shocks is administered. the base line ecg following resuscitation is shown.
WHICH OF THE FOLLOWING IS THE MOST LIKELY UNDERLYING CAUSE OF THHIS PATIENT'S
SUDDEN CARDIAC ARREST?
CORRECT ANSWER
Brugada Syndrome
Question 2
A 50-year-old man comes to the physician because of muscle weakness over the past few
months. He has drooping eyelids. Which of the following drugs would most likely confirm
the diagnosis?
A Atropine
B Bupropion
C Edrophonium
D Metoprolol
E Scopolamine
CORRECT ANSWER
Myasthenia gravis is an autoimmune disease wherein the body produces antibodies to the
post-synaptic acetylcholine receptors. Acetylcholine cannot bind its receptor at the
neuromuscular junction, thereby permitting only weak muscle contraction or blocking
muscle contraction entirely. Edrophonium is an acetylcholinesterase blocker that causes
increased acetylcholine to build in the synaptic space, enabling increased binding to the
post-synaptic receptor and inducing an action potential at the neuromuscular junction,
1
,allowing muscle contraction. If the patient improves after edrophonium administration, it is
highly suggestive of a diagnosis of myasthenia gravis
Question 3
An 89-year-old woman comes to the physician because of weight loss, fatigue, and
"mental slowing" over the past 6 months. She has a history of myocardial infarction and
percutaneous coronary intervention with stenting to the left an or descending artery
(LAD). Examination shows severe psychomotor slowing and temporal muscle wasting. Her
renal function is normal (a creatinine of 0.8mg/dl) She is unsuitable for bone marrow
transplant and is started on bortezomib
Which of the following best describes the mechanism of action of this drug?
A. Alkylating agent
B. Anti bone resorptive action
C. Immunomodulatory and anti-angiogenic effect
D. Proteasome inhibitor
E. Suppression of plasma cells
CORRECT ANSWER
Bortezamib is a novel class of drug that acts by proteasome inhibition. This results in G2-M
cell cycle arrest and Bcl-2 phosphorylation, with consequent apoptosis. This drug is also now
used in the treatment of Mantle cel lymphoma. The boron atom in bortezomib binds to 26S
proteosome and prevents degradation of pro-apopto factors.
Thus, cell iar destruction pathways are activated.
Question 4
A test has just become available to detect a new strain of hepatitis virus. In early trials
1000 people were enrolled to undergo testing. Four hundred participants had a positive
initial test, but confirmatory testing showed that only 200 people were truly infected. The
2
, remaining participants were negative by both experimental testing and confirmatory
testing. What is the specificity of this new test?
A. 40%
B. 50%
C. 70%
D. 75%
E.80%
F. 90%
G. 100%
CORRECT ANSWER
75%
Question 5
A. Herpes virus
The cell surronded by the white "halo" shown in the image is a Reed-Sternberg cell. It is
required but not sufficient for a pathologic diagnosis of Hodgkin disease. EBV, a type of
herpesvirus, is a known risk factor for Hodgkin disease, and it is associated with 50% of cases
of Hodgkin disease. Burkitt lymphoma also is associated with EBV infection.
CORRECT ANSWER
This following image was taken from a biopsy of the mediastinal lymph nodes of a 34-year-
old man with a type of lymphoma.
Which of the following types of microorganism is associated with this condition?
A. Hepadnavirus
B. Herpesvirus
C. Mycobacterium
D. Papovavirus
E. Retrovirus
3
VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
A 26 years old asian man comes to the physician because of palpitations, dizzy spells, and
intense weakness. he collapses and loses consciousness. an advanced cardiac life support
protocol is executed. with the underlying rhythm being ventricular fibrillation, a series of
electrical shocks is administered. the base line ecg following resuscitation is shown.
WHICH OF THE FOLLOWING IS THE MOST LIKELY UNDERLYING CAUSE OF THHIS PATIENT'S
SUDDEN CARDIAC ARREST?
CORRECT ANSWER
Brugada Syndrome
Question 2
A 50-year-old man comes to the physician because of muscle weakness over the past few
months. He has drooping eyelids. Which of the following drugs would most likely confirm
the diagnosis?
A Atropine
B Bupropion
C Edrophonium
D Metoprolol
E Scopolamine
CORRECT ANSWER
Myasthenia gravis is an autoimmune disease wherein the body produces antibodies to the
post-synaptic acetylcholine receptors. Acetylcholine cannot bind its receptor at the
neuromuscular junction, thereby permitting only weak muscle contraction or blocking
muscle contraction entirely. Edrophonium is an acetylcholinesterase blocker that causes
increased acetylcholine to build in the synaptic space, enabling increased binding to the
post-synaptic receptor and inducing an action potential at the neuromuscular junction,
1
,allowing muscle contraction. If the patient improves after edrophonium administration, it is
highly suggestive of a diagnosis of myasthenia gravis
Question 3
An 89-year-old woman comes to the physician because of weight loss, fatigue, and
"mental slowing" over the past 6 months. She has a history of myocardial infarction and
percutaneous coronary intervention with stenting to the left an or descending artery
(LAD). Examination shows severe psychomotor slowing and temporal muscle wasting. Her
renal function is normal (a creatinine of 0.8mg/dl) She is unsuitable for bone marrow
transplant and is started on bortezomib
Which of the following best describes the mechanism of action of this drug?
A. Alkylating agent
B. Anti bone resorptive action
C. Immunomodulatory and anti-angiogenic effect
D. Proteasome inhibitor
E. Suppression of plasma cells
CORRECT ANSWER
Bortezamib is a novel class of drug that acts by proteasome inhibition. This results in G2-M
cell cycle arrest and Bcl-2 phosphorylation, with consequent apoptosis. This drug is also now
used in the treatment of Mantle cel lymphoma. The boron atom in bortezomib binds to 26S
proteosome and prevents degradation of pro-apopto factors.
Thus, cell iar destruction pathways are activated.
Question 4
A test has just become available to detect a new strain of hepatitis virus. In early trials
1000 people were enrolled to undergo testing. Four hundred participants had a positive
initial test, but confirmatory testing showed that only 200 people were truly infected. The
2
, remaining participants were negative by both experimental testing and confirmatory
testing. What is the specificity of this new test?
A. 40%
B. 50%
C. 70%
D. 75%
E.80%
F. 90%
G. 100%
CORRECT ANSWER
75%
Question 5
A. Herpes virus
The cell surronded by the white "halo" shown in the image is a Reed-Sternberg cell. It is
required but not sufficient for a pathologic diagnosis of Hodgkin disease. EBV, a type of
herpesvirus, is a known risk factor for Hodgkin disease, and it is associated with 50% of cases
of Hodgkin disease. Burkitt lymphoma also is associated with EBV infection.
CORRECT ANSWER
This following image was taken from a biopsy of the mediastinal lymph nodes of a 34-year-
old man with a type of lymphoma.
Which of the following types of microorganism is associated with this condition?
A. Hepadnavirus
B. Herpesvirus
C. Mycobacterium
D. Papovavirus
E. Retrovirus
3
