USMLE-Rx Step 1 Practice Q's

USMLE-Rx Step 1 Qmax Challenge #1176

Check out today’s Step 1 Qmax Question Challenge.

Know the answer? Post it below! Don’t forget to check back for an update with the correct answer and explanation (we’ll post it in the comments section below).

usmle-rx-step-1-qmax-challenge-1176A 44-year-old former alcoholic woman presents with worsening fatigue for the past 2 months. She reports no other symptoms, and physical examination is unremarkable. Laboratory studies reveal a hemoglobin level of 8 g/dL and mean corpuscular volume of 110 μm³. The blood smear shown in the image was obtained as part of her work-up.

Which of the following is the function of the vitamin causing this patient’s condition?

A. Catalyzes γ-carboxylation of glutamic acid residues
B. Hydroxylates prolyl and lysyl residues
C. Increases intestinal calcium and phosphate absorption
D. Makes up the constituents of the visual pigments
E. Transfers single-carbon intermediates


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4 replies »

  1. probably the answer gonna be E. which is Vitamin B9(folate) single-carbon transfer, also most common vit deff, in USA in Alcoholics mostly, causing megaloblastic anemia which is MCV more then 90fL, and hypersegmented PMN cells, and no neurological symptoms.


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