Oogenesis is the process of development and maturation of eggs in the ovaries. This process involves various stages of development of the immature ovum into the ovarian follicle and consists of sub processes such as oocytogenesis, ootidogenesis and maturation. In plants, oogenesis occurs inside the female gametophyte through the process of mitosis.

Oogenesis is the process by which oogonia (primitive female egg cell developed during fetal development) becomes a zygote (the result of the mating of sperm and egg). During the first phase, the oogonia start meiosis but are stopped at prophase meiosis I during fetal development. During the second phase, increasing levels of FSH (follicle stimulating hormone) during puberty cause the primary follicular cells to grow and start producing estrogen. In the third phase, the secondary oocyte begins meiosis II and stops in metaphase. A secondary oocyte is ovulated. If the oocyte is fertilized, meisosis II resumes. The oocyte splits into an ovum and a second polar body. The sperm and ovum unite and form a diploid zygote.

I have my biology test tomorrow, and the only subject matter that I don't understand is oogenesis. I know that is like spermatogenesis, but occurs in eggs, but that is really all that I understand. I also know that it has to do with the degeneration of polar bodies, but I really just don't get it. Please explain in detail. I'm really having trouble with this. Thanks in advance!