Genetics: 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 · Genetics

Sample item

What is a deletion mutation?

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

The answer and the reasoning

B. Loss of one or more nucleotides from DNA

A deletion removes nucleotides from a DNA sequence and can cause a frameshift if the number deleted is not divisible by three.

Option by option

  • A. Duplication of every chromosome

    Whole-genome duplication is a different event.

  • B. Loss of one or more nucleotides from DNA (correct)

    Correct: deletion means loss of sequence.

  • C. Addition of a methyl group only

    Methylation is epigenetic modification.

  • D. Substitution of one purine for another only

    Substitution exchanges bases.

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, Loss of one or more nucleotides from DNA. A deletion removes nucleotides from a DNA sequence and can cause a frameshift if the number deleted is not divisible by three.

Why is "Duplication of every chromosome" not the answer?

Whole-genome duplication is a different event.

Why is "Addition of a methyl group only" not the answer?

Methylation is epigenetic modification.

Why is "Substitution of one purine for another only" not the answer?

Substitution exchanges bases.

What concept does this question test?

It tests Genetics in Biochemistry. The correct option holds because: Correct: deletion means loss of sequence.

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 Genetics?

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.