Question

In oogenesis haploid egg is fertilised by sperm at which stage?

• A. Primary oocyte
• B. Secondary oocyte
• C. Oogonium
• D. None of the above
  

Answer 1

The correct option is B Secondary oocyte

Oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each foetal ovary. These cells start division and enter into prophase - I of the meiotic division and get temporarily arrested at that stage, called primary oocytes. This eventually undergoes unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body. The Graafian follicle (mature follicle) eventually ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation. After ovulation, this secondary oocyte travels to the fallopian tube where it is fertilised by a sperm.