Biotransformation: cytochrome P450: 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.

Try it

Biochemistry · Biotransformation: cytochrome P450

Sample item

What is the main role of phase I cytochrome P450 reactions in drug metabolism?

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

The answer and the reasoning

C. Introduce or expose functional groups through oxidation, reduction, or hydrolysis

Phase I metabolism often uses cytochrome P450 enzymes to create or reveal functional groups, sometimes generating reactive intermediates. Phase II reactions conjugate compounds to increase water solubility.

Option by option

  • A. Eliminate all drugs unchanged through bile

    Many drugs require metabolic transformation before excretion.

  • B. Conjugate drugs directly with glucuronic acid only

    Glucuronidation is a phase II conjugation reaction.

  • C. Introduce or expose functional groups through oxidation, reduction, or hydrolysis (correct)

    Correct. Functionalization reactions define phase I metabolism.

  • D. Synthesize plasma albumin

    Albumin is synthesized by hepatocytes but not by drug-metabolism enzymes.

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.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is C, Introduce or expose functional groups through oxidation, reduction, or hydrolysis. Phase I metabolism often uses cytochrome P450 enzymes to create or reveal functional groups, sometimes generating reactive intermediates.

Why is "Eliminate all drugs unchanged through bile" not the answer?

Many drugs require metabolic transformation before excretion.

Why is "Conjugate drugs directly with glucuronic acid only" not the answer?

Glucuronidation is a phase II conjugation reaction.

Why is "Synthesize plasma albumin" not the answer?

Albumin is synthesized by hepatocytes but not by drug-metabolism enzymes.

What concept does this question test?

It tests Biotransformation: cytochrome P450 in Biochemistry. Phase II reactions conjugate compounds to increase water solubility.

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 Biotransformation: cytochrome P450?

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.