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Difficulty: MediumReproductive Systems and Processes in Organisms

Arrange the following stages of mammalian spermatogenesis in the correct sequence from the initial diploid stem cell division to the formation of functional gametes.

  1. 1Mitotic division of diploid spermatogonia to yield primary spermatocytes.
  2. 2First meiotic division (Meiosis I) of primary spermatocytes to form haploid secondary spermatocytes.
  3. 3Second meiotic division (Meiosis II) of secondary spermatocytes to produce haploid spermatids.
  4. 4Spermiogenesis involving structural differentiation of spermatids into mature, motile spermatozoa.

Answer

The correct chronological sequence is: Mitotic division of diploid spermatogonia to yield primary spermatocytes → First meiotic division (Meiosis I) of primary spermatocytes to form haploid secondary spermatocytes → Second meiotic division (Meiosis II) of secondary spermatocytes to produce haploid spermatids → Spermiogenesis involving structural differentiation of spermatids into mature, motile spermatozoa.
The proper developmental pathway follows cellular multiplication by mitosis (spermatogonia to primary spermatocytes), followed by reduction division in Meiosis I (forming secondary spermatocytes), equational division in Meiosis II (forming spermatids), and finally cellular differentiation during spermiogenesis (producing spermatozoa).

Step-by-Step Solution

1
Identify the starting germ cell and multiplication phase.
Spermatogonia (diploid) undergo mitosis to maintain the stem cell population and produce primary spermatocytes.
Gametogenesis begins with mitotic multiplication before meiotic reduction can take place.
2
Determine the first reductional division stage.
Primary spermatocytes enter Meiosis I, resulting in haploid secondary spermatocytes.
Homologous chromosomes separate during Meiosis I, reducing ploidy from 2n2n to nn.
3
Identify the second meiotic division stage.
Secondary spermatocytes complete Meiosis II to form spherical haploid spermatids.
Sister chromatids separate during Meiosis II to yield four genetically distinct haploid cells.
4
Identify the final differentiation phase.
Spermatids undergo spermiogenesis to transform into mature spermatozoa.
Physical metamorphosis (loss of cytoplasm, formation of flagellum and acrosome) is required for motility and fertilization capability.

Key Concept

Sequence of Spermatogenesis
Estimated Time:1m 30s
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Topics

Reproductive Systems and Processes in Organisms

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