Question

100 primary oocytes will form how many eggs?

Answer 1

Ovaries are the primary female sex organs that produce the female gametes (ovum) and several steroid hormones (ovarian hormones). Each ovary is an almond-like flattened body, measuring about 2 to 4 cm in length. Oocytes is a cell in an ovary which may undergo meiotic division to form an ovum.

Complete answer:
The process of formation of a mature female gamete is called oogenesis. It occurs in the ovaries and consists of the following of 3 phases-
Multiplication phase- oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each foetal ovary. No more oogonia are formed after birth. These cells start dividing called primary oocytes.

Growth phase- Each primary oocyte is surrounded by a layer and forms a structure called a primary follicle. These follicles degenerate during the phase from birth to puberty. Then, these primary follicles get surrounded by more layers and from secondary follicles.

Maturation phase- In this phase, the secondary follicle soon transformed into a tertiary follicle. The primary oocyte within the tertiary follicle grows in size and completes its first meiotic division to form a large haploid secondary oocyte and a first tiny polar body that ruptures from the ovary by a process called ovulation. The second meiotic division results in the formation of a second polar body and haploid ovum (ootid).

So, if one primary oocyte gives rise to one egg at a time then, 100 primary oocytes give rise to 100 eggs.

Note:
- Oogenesis is completed when the sperm cell penetrates the ovum. The oocyte is an immature egg cell and one of the largest cells in the body (approx. 110 µm in diameter) and a specialized unit of the ovary.
- As many as 700000 primary follicles are contained in the two ovaries of a young female. Oocyte is surrounded by an epithelium.