what is oogenesis?with full explanation
Answers
Heya!
Here is ur answer....
OOGENESIS :
>>OOGENESIS can be defined as the differentiation of Ovum into a cell
>> It differentiate into cell..for the further developement
>> This process is also called as OVOGENESIS
>> This process occurs only in womans...
Hope it helps
Oogenesis
The diploid cells which are capable of developing into ova are known as oogonia. Every female’s oogonia are formed when she’s still a fetus and has not even born. Moreover, around one or two months before a girl baby is born, over seven million oogonia vanish and the survived oogonia move towards meiosis I and become primary oocytes. These oocytes pause their advancement in prophase I soon after replicating their genomes. They stay paused for a decade until a girl starts her first menstrual cycle. For the next 30-40 years, primary oocytes retrieve meiosis from where they left and finish the first meiotic division on monthly basis.
When primary oocyte does complete its first meiotic division, it separates the chromosomes evenly but does not separate cytoplasm evenly. Almost whole cytoplasm stays in one of the two daughter cells that become a secondary oocyte. The development of a polar body enables the primary oocyte to minimize its genome by half and save most of its cytoplasm in the secondary oocyte.
Secondary oocyte still holds two copies of the chromosome and has to undergo second meiotic division. This is also not even similar to first with half of the chromosomes moving to another small degenerate polar body and the other half get retrieved by the ovum with the whole cytoplasm.