In which of the following transmissions meiosis occurs :
Ans. is a i.e. Primary to secondary spermatocyte The process involved in the development of spermatids from the primordial male germ cells and their -!Werentiation into spermatoznq (or sperms) is called as spermatogenesis. Sholy before pubey. the primordial germ cells develop into sperrnatogonia in the wall of seminiferous tubules. Meiosis is a special type of cell division that reduces the diploid number of chromosomes (i.e., 46) to the haploid number of 23. It takes place only in germ cells; to give rise to gametes (sperms and egg cells) It involves two meiotic cell divisions, meiosis I and meiosis II. The first metotic division is a reduction division because the chromosome number is reduced from diploid (46) to haploid (23). The 2nd meiotic division is similar to mitosis as daughter cells formed contain the same haploid number of chromosomes as the mother cell. Thus. though nation 'a' and both are correct but reduction division occurs when primary spermatocyte is transformed to secondary spermatocyte, so it is the answer of choice. Extra Edae : The developmental process from spermatogonium to sperm takes about 61 daysdeg and the entire process, including the transit time in the ductal system takes approximately three months.deg Clinical significance The above fact is clinically significant, as in case of male factor infeility a repeat semen analysis to see the sperm count, motility etc. after giving treatment should be ;,,ne three months the first analysis (as new sperms will be formed after 3 months).
Primary to secondary spermatocyte
Second spermatocyte to globular spermatid
Germ cells to spermatogonium
Spermatogonium to primary spermatocyte