Question
Question: 10 oogonia yield 10 primary oocytes then how many ova are produced on completion of oogenesis a) ...
10 oogonia yield 10 primary oocytes then how many ova are produced on completion of oogenesis
a) 5
b) 10
c) 20
d) 40
Solution
Oogonia are the female reproductive cells that give rise to primary oocytes (carrying female genetic material) by the process of oogenesis. Oogonia are immature cells that arise from Primordial Germ cells by mitotic division.
Complete Step by Step Answer
Oogenesis is a process of formation of the female gamete. Major stages of this process are completed in foetal stage of the female individual. Therefore, puberty involves only maturation of these reproductive cells. Till the foetal stage, primordial germ cells divide and develop to form primary oocytes.
After the birth of a female child, these primary oocytes undergo meiotic division and form follicular cells. However, this meiotic division continues till puberty along with every menstrual cycle. At the beginning of the menstrual cycle, this meiotic division completes and one of the follicular cells divides to form two unequal cells. One is bigger in size called secondary oocyte while the other is smaller in size called polar body. This polar body keeps dividing while the secondary oocyte grows in size to mature. Later the secondary oocytes eventually develop to form the female gamete by the action of Luteinizing Hormone whereas the polar body divides and develops to form surrounding follicular cells. These follicular cells are further acted upon by Follicle Stimulating Hormone that helps in maintaining secondary female characters.
Therefore, every menstrual cycle involves formation of only one functional cell (ova) from a primary oocyte. This implies that 10 primary oocytes would yield formation of 10 ova on completion of the process of oogenesis.
Thus, option B is the correct answer.
Note:
As the menstrual cycle takes place every month after the attainment of puberty. As these primary oocytes are limited in number, they finish till the age of 45 to 50. This is the reason for which females lose their reproductive abilities after a certain age limit.