Enzymology: allosteric regulation: 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 · Enzymology: allosteric regulation

Sample item

Which feature is characteristic of an allosteric enzyme?

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

The answer and the reasoning

C. A sigmoidal substrate-velocity curve

Allosteric enzymes often show cooperative substrate binding and a sigmoidal velocity curve. They are commonly regulated by metabolites that stabilize different conformational states.

Option by option

  • A. A strictly linear velocity curve at all substrate levels

    Michaelis-Menten hyperbolic kinetics are more typical of nonallosteric enzymes.

  • B. No regulation by metabolites

    Allosteric enzymes are often strongly metabolically regulated.

  • C. A sigmoidal substrate-velocity curve (correct)

    Correct. Cooperativity produces sigmoidal kinetics.

  • D. Only one active site in every case

    They commonly have multiple subunits or interacting sites.

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 C, A sigmoidal substrate-velocity curve. Allosteric enzymes often show cooperative substrate binding and a sigmoidal velocity curve.

Why is "A strictly linear velocity curve at all substrate levels" not the answer?

Michaelis-Menten hyperbolic kinetics are more typical of nonallosteric enzymes.

Why is "No regulation by metabolites" not the answer?

Allosteric enzymes are often strongly metabolically regulated.

Why is "Only one active site in every case" not the answer?

They commonly have multiple subunits or interacting sites.

What concept does this question test?

It tests Enzymology: allosteric regulation in Biochemistry. They are commonly regulated by metabolites that stabilize different conformational states.

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 Enzymology: allosteric regulation?

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.