Minerals: zinc deficiency: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Biochemistry · Minerals: zinc deficiency

Sample item

A 5-month-old weaned from breast milk develops a perioral and perianal vesiculobullous rash, diarrhoea and hair loss. A mutation in SLC39A4 is found. Which serum enzyme activity is expected to be low?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Alkaline phosphatase

The picture is acrodermatitis enteropathica, an inherited defect of the intestinal zinc transporter ZIP4, so breast milk zinc is adequate until weaning. Alkaline phosphatase is a zinc metalloenzyme, and a low serum level with a low plasma zinc supports the diagnosis. Lifelong oral zinc is curative.

Option by option

  • A. Glutathione peroxidase

    Glutathione peroxidase is a selenoprotein.

  • B. Cytochrome c oxidase

    Cytochrome c oxidase depends on copper and iron.

  • C. Lysyl oxidase

    Lysyl oxidase is a copper-dependent enzyme.

  • D. Alkaline phosphatase (correct)

    Alkaline phosphatase requires zinc, so its activity falls in zinc deficiency.

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.

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Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is D, Alkaline phosphatase. The picture is acrodermatitis enteropathica, an inherited defect of the intestinal zinc transporter ZIP4, so breast milk zinc is adequate until weaning.

Why is "Glutathione peroxidase" not the answer?

Glutathione peroxidase is a selenoprotein.

Why is "Cytochrome c oxidase" not the answer?

Cytochrome c oxidase depends on copper and iron.

Why is "Lysyl oxidase" not the answer?

Lysyl oxidase is a copper-dependent enzyme.

What concept does this question test?

It tests Minerals: zinc deficiency in Biochemistry. Alkaline phosphatase is a zinc metalloenzyme, and a low serum level with a low plasma zinc supports the diagnosis. Lifelong oral zinc is curative.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Minerals: zinc deficiency?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.