Question

Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

Answer 1

Meiosis during spermatogenesis:

During spermatogenesis the primary spermatocyte undergoes meiosis I to form two secondary spermatocytes which further undergoes meiosis II to form four spermatids.
The spermatids are transformed into sperms.


The spermatogenesis in human male is a continuous process that starts with the onset of puberty



Meiosis during oogenesis:

During oogenesis oogonia undergoes meiosis I but is arrested at prophase I and forms primary oocyte. The primary oocyte during puberty completes the first meiotic division forming the first polar body and secondary oocyte.

Secondary oocyte begins meiosis II and it is arrested in the metaphase of meiosis II. It is ovulated in this stage and during the time of fertilization it completes meiosis forming ootid and second polar body. The ootid changes into ovum.

As a result of meiosis three non functional polar bodies and one functional ovum are formed.



Meiotic division of oogenesis differs from spermatogenesis:


During oogenesis the ovum retains much of the cytoplasm for further development and the polar bodies have less amount of cytoplasm, they are formed to reduce the number of chromosomes and do not have any function.

In spermatogenesis meiosis results in the production of 4 sperms.