Carbohydrate metabolism: fructose: 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 · Carbohydrate metabolism: fructose

Sample item

An infant develops vomiting, jaundice and hypoglycaemia after fruit juice is introduced. Accumulation of fructose-1-phosphate points to deficiency of which enzyme?

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

The answer and the reasoning

A. Aldolase B

Hereditary fructose intolerance results from aldolase B deficiency. Trapped fructose-1-phosphate depletes phosphate and impairs gluconeogenesis and glycogenolysis.

Option by option

  • A. Aldolase B (correct)

    Correct. Aldolase B cleaves fructose-1-phosphate.

  • B. Phosphoglucomutase

    Phosphoglucomutase interconverts glucose-1-phosphate and glucose-6-phosphate.

  • C. Fructokinase

    Fructokinase deficiency causes benign essential fructosuria.

  • D. Galactokinase

    Galactokinase deficiency causes galactitol-related cataracts.

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 A, Aldolase B. Hereditary fructose intolerance results from aldolase B deficiency.

Why is "Phosphoglucomutase" not the answer?

Phosphoglucomutase interconverts glucose-1-phosphate and glucose-6-phosphate.

Why is "Fructokinase" not the answer?

Fructokinase deficiency causes benign essential fructosuria.

Why is "Galactokinase" not the answer?

Galactokinase deficiency causes galactitol-related cataracts.

What concept does this question test?

It tests Carbohydrate metabolism: fructose in Biochemistry. Trapped fructose-1-phosphate depletes phosphate and impairs gluconeogenesis and glycogenolysis.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Carbohydrate metabolism: fructose?

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.