USMLE-Rx Step 1 Qmax Challenge #1751

Check out today’s Step 1 Qmax Question Challenge.

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A 38-year-old man comes to the physician 1 week after noticing a painless, red lesion on the side of his penis. He initially assumed it was the result of friction during intercourse. The patient is sexually active with several partners. Physical examination reveals a small ulcer on the patient’s penis (shown in the image).

Which of the following is the mechanism of action of the first-line therapy for his condition?

A. Blocks peptide bond formation at the 50S ribosomal subunit, interfering with bacterial replication
B. Causes bacterial cell death by inhibiting DNA gyrase
C. Causes cell lysis by interfering with transpeptidase cross-linking of cell wall
D. Gives rise to p-aminobenzoic acid anti-metabolites, leading to the inhibition of dihydropteroate synthase
E. Gives rise to reactive intermediates, leading to reduced synthesis of protein, nucleotides, and the cell wall
F. Inhibits DNA-dependent RNA polymerase

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