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Q.Given below are a few statements with respect to spermatogenesis in a human male.

(i) Sperms are released from the seminiferous tubules by the process of spermiation.
(ii) Spermiogenesis involves the maturation of spermatids into sperms.
(iii) Spermatogonia produce spermatids by the process of spermiogenesis.
(iv) Meiosis II in secondary spermatocytes results in the formation of four equal haploid spermatids.
(v) Primary spermatocyte completes the first meiotic division forming two equal, diploid cells called secondary spermatocytes. Choose the option with all true statements from the given options : (A) (i),
(ii) and
(iv) (B) (ii),
(iii) and
(v) (C) (ii),
(iv) and
(v) (D) (i),
(iii) and (iv)
CBSECBSE Class XII Board 2025MCQ· 1mImportance★★★★★
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Spermatogenesis involves the transformation of spermatogonia into mature sperms through meiosis and differentiation, culminating in their release from the seminiferous tubules.

Spermatogenesis is the intricate process by which immature male germ cells, called spermatogonia, develop into mature spermatozoa (sperms) within the seminiferous tubules of the testes. This process begins at puberty and continues throughout a male's life, ensuring a continuous supply of gametes for reproduction. It involves a series of mitotic divisions, meiotic divisions, and a final differentiation phase.

Let's break down the key stages and then evaluate the given statements:

  • Spermatogonia: These are diploid (2n) undifferentiated germ cells located on the inside wall of the seminiferous tubules. They multiply by mitotic division, increasing their numbers. Some spermatogonia differentiate into primary spermatocytes.
  • Primary Spermatocytes: These are also diploid (2n) cells. Each primary spermatocyte then undergoes the first meiotic division (Meiosis I). This is a reductional division, meaning the chromosome number is halved.
  • Secondary Spermatocytes: After Meiosis I, each primary spermatocyte forms two equal, haploid (n) cells called secondary spermatocytes. These cells have 23 chromosomes, each with two chromatids.
  • Spermatids: Each secondary spermatocyte then rapidly undergoes the second meiotic division (Meiosis II). This is an equational division, similar to mitosis, where sister chromatids separate. As a result, two equal, haploid (n) spermatids are formed from each secondary spermatocyte. Therefore, from one primary spermatocyte, a total of four haploid spermatids are produced.
  • Spermiogenesis: This is the process of differentiation where the non-motile, round spermatids are transformed into elongated, motile spermatozoa (sperms). During this phase, the spermatids develop a head, middle piece, and tail.
  • Spermiation: After spermiogenesis, the heads of the newly formed sperms become embedded in the Sertoli cells (nurse cells) for nourishment. Once mature, they are finally released from the seminiferous tubules by a process known as spermiation.

Now, let's evaluate each statement:

  • (i) Sperms are released from the seminiferous tubules by the process of spermiation.

    • This statement is True. As described above, spermiation is the final step where mature spermatozoa are released from the Sertoli cells into the lumen of the seminiferous tubules.
  • (ii) Spermiogenesis involves the maturation of spermatids into sperms.

    • This statement is True. Spermiogenesis is precisely the morphological transformation and differentiation of haploid spermatids into mature, motile spermatozoa.
  • (iii) Spermatogonia produce spermatids by the process of spermiogenesis. …

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