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Write the main steps to… (Class 10 Science 2025, Q24b)

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ScienceCBSE Class 10 · Board exam 2025, set 31/2/1 · 2 marks · Very short answer

CBSE Class 10 Science 2025: question 24(b)

Set in the CBSE Class 10 board exam of 2025, paper 31/2/1, section B, question 24(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q24(b) · 2 marks · Very short answerHow do Organisms Reproduce?

Write the main steps to culture yeast in the laboratory.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/2/1.

Hints

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

Hint 1

Yeast is a living organism. What does it need as food to grow?

Hint 2

Think of a sugar solution and a warm place. How long should the yeast be left in it?

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. Prepare a sugar solution: put about 10 g of sugar in a test tube (or small flask) and dissolve it in about 100 mL of water. The sugar is the food for the yeast cells.

    1 mark

  2. Add a pinch of yeast granules to the sugar solution. Keep the test tube in a warm place for 1–2 hours. The warmth helps the yeast cells grow and multiply. Yeast has now been cultured.

    1 mark

  3. (To observe it, put a drop of the culture on a slide and see it under a microscope. Yeast cells with small buds, i.e. budding, are seen.)

Answer: Dissolve ~10 g sugar in 100 mL water in a test tube, add a pinch of yeast granules, and keep it in a warm place for 1–2 hours.

Where the marks are

  • Takes sugar solution (about 10 g sugar in 100 mL water) (1 mark)
  • Adds a pinch of yeast and keeps it warm for 1–2 hours (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from How do Organisms Reproduce?, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/2/1: 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.