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Drug-use disorders… (Class 12 Biology SQP 2026-27, Q26)

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BiologyCBSE Class 12 · Sample paper, session 2026-27 · 3 marks · Short answer

CBSE Class 12 Biology sample paper 2026-27: question 26

From the official CBSE sample question paper for 2026-27, section C, question 26, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 3 marks · Short answerCompetency-basedHuman Health and Disease

Drug-use disorders often begin with occasional consumption but may progress into a compulsive state.
Analyse how addiction differs from dependence in both origin and consequence, and justify why long-term drug intake forces the user to increase dose over time.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

Open one hint at a time and try again before the next.

Hint 1

One is about the mind and the other is about the body.

Hint 2

Think about what happens to the body's receptors after repeated exposure to a drug.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Addiction: its origin is psychological. It is an attachment to certain effects of the drug, such as euphoria and a temporary feeling of well-being. Its consequence is that the person keeps taking the drug even when it is not needed, which leads to compulsive use.

    1 mark

  2. Dependence: its origin is physical. The body comes to rely on the drug. Its consequence is that withdrawal symptoms (anxiety, shakiness, nausea, sweating) appear when regular intake is abruptly stopped.

    1 mark

  3. Why the dose increases: repeated use raises the tolerance level of the body's receptors. The receptors then respond only to higher doses to give the same effect, so the user is forced to increase the dose over time.

    1 mark

Answer: Addiction is a psychological attachment to euphoria; dependence is physical, shown by withdrawal symptoms. Increased tolerance of the receptors makes higher doses necessary.

Where the marks are

  • Addiction as a psychological attachment to euphoric effects (1 mark)
  • Dependence as physical, shown by withdrawal symptoms on stopping (1 mark)
  • Increased receptor tolerance means higher doses are needed for the same effect (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Human Health and Disease, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.