Radiobiology: DNA damage: practice question

A Radiology 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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Radiology · Radiobiology: DNA damage

Sample item

Which type of DNA damage is the most important lethal lesion caused by ionising radiation?

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

The answer and the reasoning

A. Double-strand break

Double-strand breaks are difficult to repair accurately and are the main cause of cell death through chromosome aberrations. Single-strand breaks are readily repaired. Thymine dimers arise from UV light.

Option by option

  • A. Double-strand break (correct)

    Correct. DNA double-strand breaks are the critical lethal event.

  • B. Thymine dimer from UV

    Thymine dimers are UV-induced.

  • C. Single base methylation

    Base methylation is an alkylating agent effect.

  • D. Purine depurination

    Depurination is a spontaneous chemical lesion.

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 Radiology question

What is the answer to this Radiology question?

The best answer is A, Double-strand break. Double-strand breaks are difficult to repair accurately and are the main cause of cell death through chromosome aberrations.

Why is "Thymine dimer from UV" not the answer?

Thymine dimers are UV-induced.

Why is "Single base methylation" not the answer?

Base methylation is an alkylating agent effect.

Why is "Purine depurination" not the answer?

Depurination is a spontaneous chemical lesion.

What concept does this question test?

It tests Radiobiology: DNA damage in Radiology. Single-strand breaks are readily repaired. Thymine dimers arise from UV light.

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 Radiobiology: DNA damage?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.