Practice Test 6 - USMLE Step 1
20 questions. Answer them in any order, then submit to see your score and every explanation.
- The deleted DNA segment in this patient most likely functions as which of the following?
- What is the primary mechanism of action of a superantigen toxin?
- Which of the following best describes the mechanism of action of the administered drug?
- A case-control study evaluates whether occupational silica exposure is associated with rheumatoid arthritis (RA). Cases are 190 adults (70% women) with new RA diagnosis from rheumatology clinics. Controls are 190 adults without RA from the same health system, matched by age and sex. Exposure is determined by structured interview about past jobs and duration of dust exposure, aided by photographs of common workplace materials. Results: 34% of cases vs 20% of controls report silica exposure. Investigators note some participants struggle to recall jobs from decades earlier. Which bias is most likely to affect the results of this study?
- The development of female external genitalia in this patient is due to the failure of which of the following embryological processes?
- This infant's condition is most likely caused by a deficiency of which of the following enzymes?
- Administration of the live attenuated measles, mumps, and rubella (MMR) vaccine would be contraindicated in this patient due to the risk of which of the following?
- The dicrotic notch on the aortic pressure waveform corresponds most closely with which of the following events in the cardiac cycle?
- The seizure focus is most likely located in the primary somatosensory cortex of which cerebral hemisphere and region?
- Based on this data, which of the following best describes the elimination kinetics of this drug?
- Which of the following is the primary mechanism of action of this medication for treating her hypertension?
- Which of the following cytokines is most likely being administered?
- Which of the following best describes the mechanism of action of the prescribed medication?
- An investigator is the lead author of a study evaluating a drug manufactured by a company in which he owns significant stock options. The IRB approves the protocol. Which additional step is ethically required before participant enrollment?
- Which of the following pathophysiologic processes is most likely responsible for this patient's renal dysfunction?
- The location most likely to be affected by this process is the splenic flexure, due to its vulnerability as a watershed area between the territories of which two arteries?
- Which of the following technologies is best suited for this comprehensive gene expression analysis?
- The elevated parathyroid hormone level in this patient is primarily a response to which of the following renal abnormalities?
- Which of the following classes of pattern recognition receptors is most directly involved in recognizing the β-glucans of the fungal cell wall?
- The severe course of this child's viral infection is primarily attributed to the impairment of which component of the immune system by malnutrition?