Molecular biology and genetics: whole-exome sequencing: 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 · Molecular biology and genetics: whole-exome sequencing

Sample item

A child has an undiagnosed syndromic intellectual disability. Karyotype and chromosomal microarray are normal. Which test is best suited to find a single-gene variant by examining the protein-coding regions of the genome?

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

The answer and the reasoning

B. Whole-exome sequencing

Whole-exome sequencing captures and sequences the coding exons, where most disease-causing variants of Mendelian disorders lie. Karyotype and microarray detect only large structural or copy-number changes. FISH and Southern blotting test single targeted loci.

Option by option

  • A. G-banded karyotype

    Karyotype shows only gross chromosomal abnormalities.

  • B. Whole-exome sequencing (correct)

    Correct. Exome sequencing reads coding regions at single-base resolution.

  • C. Fluorescence in situ hybridisation

    FISH tests a specific locus selected in advance.

  • D. Southern blotting

    Southern blotting tests a single known locus.

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 B, Whole-exome sequencing. Whole-exome sequencing captures and sequences the coding exons, where most disease-causing variants of Mendelian disorders lie.

Why is "G-banded karyotype" not the answer?

Karyotype shows only gross chromosomal abnormalities.

Why is "Fluorescence in situ hybridisation" not the answer?

FISH tests a specific locus selected in advance.

Why is "Southern blotting" not the answer?

Southern blotting tests a single known locus.

What concept does this question test?

It tests Molecular biology and genetics: whole-exome sequencing in Biochemistry. Karyotype and microarray detect only large structural or copy-number changes. FISH and Southern blotting test single targeted loci.

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 Molecular biology and genetics: whole-exome sequencing?

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.