Question

What are the cells that primary oocyte divides into called?

• A. Ovum and second polar body
• B. First polar body and second polar body
• C. Secondary oocyte and second polar body
• D. Secondary oocyte and first polar body

Answer 1

The correct option is D Secondary oocyte and first polar body

Oogenesis is the process by which mature female gametes or ova develop from germ cells. Oogenesis starts during the early embryonic development stage. At this stage, some million oogonia are formed within each foetal ovary.
Oogonia divides to form primary oocyte. Further the primary oocyte gets temporarily arrested at prophase I of meiosis.

Between birth and puberty, a large number of primary oocytes gets degenerated.

At the reproductive stage, the primary oocyte completes meiosis I to form a large haploid secondary oocyte and a tiny first polar body. This division is asymmetric. The secondary oocyte starts undergoing meiosis II but is arrested at metaphase II.

The tertiary follicle further changes into mature follicle or graafian follicle. The graafian follicle rupture to release the secondary oocyte by the process called ovulation. The secondary oocyte enters the fallopian tube and completes meiosis II upon the entry of sperm. It forms a large ovum and a second polar body after division.