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Biochemistry · Heme metabolism
Sample itemWhat iron transport protein circulates in plasma?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
D. Transferrin
The core Heme metabolism principle identifies Transferrin as the best answer because it most directly explains the biochemical pathway or tissue response described in the stem.
Option by option
A. Ferritin
Ferritin does not match the stated heme metabolism mechanism.
B. Albumin
Albumin is relevant in another context but is not the best answer here.
C. Haptoglobin
Haptoglobin does not account for the central finding in this sample.
D. Transferrin (correct)
Correct. Transferrin is supported by the key clue given.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.