Female gametogenesis or oogenesis produces mature eggs. Only one egg is produced from 4 haploid cells as a result of meiosis. Oogenesis proceeds with primary oocyte undergoing first meiotic division forming secondary oocyte (haploid). Secondary oocytes undergo second meiosis division forming a haploid ovum (if fertilized by sperm).
Hence, one egg results from meiosis, which contains the most nutrients, cytoplasm, organelles. The unequal distribution of substances gives rise to one large cell, and one cell with more DNA (polar body which gradually degenerates). The larger cell undergoes meiosis II producing a polar body and a large cell again, and this large cell becomes the ovum.
- Why Does Spermatogenesis Result in Four Spermatids but Oogenesis Only in One Ovum?
- Why Does Only One Egg Rather Than four Eggs Develop During Oogenesis?
- Do Oocytes Undergo Mitosis?