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Study the given diagram… (Class 12 Biology 2025, Q32a)

questionbuddy.in/q/cbse-12-biology-2025-57-7-1-q32a-diagram-showing-sectional-view-seminiferous

BiologyCBSE Class 12 · Board exam 2025, set 57/7/1 · 5 marks · Long answer

CBSE Class 12 Biology 2025: question 32(a)

Set in the CBSE Class 12 board exam of 2025, paper 57/7/1, section E, question 32(a), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q32(a) · 5 marks · Long answerHuman Reproduction

Study the given diagram showing the sectional view of a seminiferous tubule.
Answer the following questions :
(i) Label A, B, C and D in the figure. (2)
(ii) What will be the number of chromosomes in secondary spermatocyte and spermatid respectively ? (1)
(iii) Explain the terms – Spermiogenesis and Spermiation. (2)

Figure in the paper: Sectional view of a seminiferous tubule with labels A (pointing to sperms with tails at lumen side), Secondary spermatocyte, B, Primary spermatocyte, C, D (towards the outer wall); A, B, C, D to be labelled. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 57/7/1.

Hints

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

Hint 1

Follow the order of cells from the tubule wall to the lumen: spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid, sperm.

Hint 2

Both cells in (ii) are formed after meiosis I, so think about ploidy. In (iii), one term means transformation and the other means release.

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) A – Spermatozoa (sperms with tails, towards the lumen)

    ½ mark

  2. B – Spermatid

    ½ mark

  3. C – Sertoli cell

    ½ mark

  4. D – Spermatogonium (near the outer wall)

    ½ mark

  5. (ii) Secondary spermatocyte: 23 chromosomes (haploid, formed after meiosis I).

    ½ mark

  6. Spermatid: 23 chromosomes (haploid, formed after meiosis II).

    ½ mark

  7. (iii) Spermiogenesis: the process by which spermatids are transformed into spermatozoa (sperms).

    1 mark

  8. Spermiation: the process by which sperms, whose heads are embedded in the Sertoli cells, are released from the seminiferous tubules.

    1 mark

Answer: (i) A: Spermatozoa, B: Spermatid, C: Sertoli cell, D: Spermatogonium; (ii) 23 and 23; (iii) Spermiogenesis turns spermatids into sperms; spermiation releases sperms from the seminiferous tubules.

Where the marks are

  • Four correct labels (½ × 4 = 2 marks)
  • 23 chromosomes in the secondary spermatocyte (½ mark) and 23 in the spermatid (½ mark)
  • Spermiogenesis defined (1 mark)
  • Spermiation defined (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Human Reproduction, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 57/7/1: 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.