Question

How many ova and sperm will be formed from 50 secondary oocytes and 50 secondary spermatocytes in frog?

• A. 50 ova and 200 sperms
• B. 50 ova and 100 sperms
• C. 100 ova and 200 sperms
• D. 100 ova and 400 sperms

Answer 1

Answer: (B)

50 ova and 100 sperms

The primary sex organs, the testis in the males and the ovaries in the females produce gametes, i.e, sperms and ovum respectively, by the process called gametogenesis. In human females, each secondary oocyte forms a single ovum just before fertilisation. The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane. This induces the completion of the meiotic division of the secondary oocyte. The second meiotic division is also unequal like the first meiotic division and results in the formation of a second polar body and a haploid ovum (ootid).
In males, each secondary spermatocyte undergoes meiosis II to produce two spermatids which later on form two spermatozoa. The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis. After spermiogenesis, sperm heads become embedded in the Sertoli cells and are finally released from the seminiferous tubules by the process called spermiation.
Thus, on completion of meiosis II, 50 secondary spermatocytes will form 100 spermatids which will eventually form 100 sperm and 50 secondary oocytes will form 50 ova.