question_answer 30)

  The immature male germ cell undergoes division to produce sperms by the process of spermatogenesis. Choose the correct one with reference to above. (a) Spermatogonia have 46 chromosomes and always undergo meiotic cell division (b)Primary spermatocytes divide by mitotic cell division (c)Secondary spermatocytes have 23 chromosomes and undergo second meiotic division (d) Spermatozoa are transformed into spermatids

Answer:

                  (b)In testis, the immature male germ cells (spermatogonia) produce sperms by spermatogenesis. The spermatogonia present on the inside wall of seminiferoustubules multiply by mitotic division and increase in numbers. Each spermatogonia is diploid and contains 46 chromosomes. 2n some of the spermatogonia called primary spermatocytes periodically undergo meiosis. A primary spermatocyte completes the first meiotic division (reduction division) leading toformation of two equal, haploid cells called secondary spermatocvtes, which have only23 chromosomes each (n). The secondary spermatocytes undergo the second phase of meiotic division to produce four equal, haploid spermatids, the spermatids are transformed into spermatozoa (spermsby the process called spermiogenesis.