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Where are auxins synthesized… (Class 10 Science 2023, Q22B)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 22(B)

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section B, question 22(B), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q22(B) · 2 marks · Very short answerControl and Coordination

Where are auxins synthesized in a plant ? Which organ of the plant shows :

  1. (i)

    Positive phototropism

    1 mark
  2. (ii)

    Negative geotropism

    1 mark
  3. (iii)

    Positive hydrotropism

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

Think of where plant growth takes place most actively.

Hint 2

'Positive' means growing towards the stimulus and 'negative' means growing away from it.

Hint 3

The stem grows up towards light, and roots grow down towards water.

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. Auxins are synthesised at the tips of the shoot (and root).

    ½ mark

  2. (i) Positive phototropism (growth towards light): shoot / stem.

    ½ mark

  3. (ii) Negative geotropism (growth away from gravity): shoot / stem.

    ½ mark

  4. (iii) Positive hydrotropism (growth towards water): roots.

    ½ mark

Answer: Auxins: at shoot tip; (i) shoot; (ii) shoot; (iii) root

Where the marks are

  • Auxin synthesised at tip of shoot (½ mark)
  • Shoot shows positive phototropism (½ mark)
  • Shoot shows negative geotropism (½ mark)
  • Root shows positive hydrotropism (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Control and Coordination, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 31/4/1: 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.