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To produce 1600 seeds… (Class 12 Biology SQP 2024-25, Q2)

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BiologyCBSE Class 12 · Sample paper, session 2024-25 · 1 mark · MCQ

CBSE Class 12 Biology sample paper 2024-25: question 2

From the official CBSE sample question paper for 2024-25, section A, question 2, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q2 · 1 mark · MCQSexual Reproduction in Flowering Plants

To produce 1600 seeds, the number of meiotic divisions required will be

  1. (A)2400
  2. (B)2000
  3. (C)1600
  4. (D)1800

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

Each seed comes from one fertilisation, which needs one pollen grain and one egg.

Hint 2

How many pollen grains come from one meiosis, and how many eggs come from one meiosis?

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. Each seed needs 1 pollen grain and 1 egg. One meiosis of a microspore mother cell gives 4 pollen grains, so 1600 pollen grains need meioses.

    ½ mark

  2. One meiosis of a megaspore mother cell gives only 1 functional megaspore, hence 1 egg. So 1600 eggs need 1600 meioses. Total . Correct option: (B).

    ½ mark

Answer: 2000, option (B)

Where the marks are

  • Calculates 400 meioses for the pollen grains and 1600 for the eggs, total 2000 (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Sexual Reproduction in Flowering Plants, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2024-25: 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.