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A farmer while working on… (Class 12 Biology 2024, Q20a)

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BiologyCBSE Class 12 · Board exam 2024, set 57/1/1 · 2 marks · Very short answer

CBSE Class 12 Biology 2024: question 20(a)

Set in the CBSE Class 12 board exam of 2024, paper 57/1/1, section B, question 20(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q20(a) · 2 marks · Very short answerCompetency-basedHuman Health and Disease

A farmer while working on his farm was bitten by a poisonous snake. He was rushed to a nearby health centre where the doctor gave him an injection to save his life.

(i) What did the doctor inject and why ? (1½)
(ii) Name the kind of immunity provided by this injection. (½)

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 57/1/1.

Hints

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

Hint 1

Would there be time for the farmer's own body to make antibodies against the venom?

Hint 2

When ready-made antibodies are given directly, what type of immunity results?

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. (i) The doctor injected anti-venom (antitoxin), which contains readymade, preformed antibodies against the snake venom.

    ½ mark

  2. (i) Snake venom acts very fast, so a quick immune response is needed. There is no time for the body to produce its own antibodies, so preformed antibodies that neutralise the toxin immediately are given.

    1 mark

  3. (ii) The immunity provided is passive immunity.

    ½ mark

Answer: (i) Anti-venom/antitoxin with preformed antibodies, given because a quick response is needed; (ii) Passive immunity

Where the marks are

  • Preformed antibodies / antitoxin against venom (½ mark)
  • Reason: immediate/quick immune response required (1 mark)
  • Passive immunity (½ 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 paper2024 board paper, set 57/1/1: 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.