How many functional egg cells are produced from a primary oocyte that completes meiosis?

In the process of oogenesis, which is the formation of egg cells (oocytes) in females, a primary oocyte undergoes meiosis to develop into a mature egg cell. During meiosis, this primary oocyte undergoes two rounds of cell division: meiosis I and meiosis II.

At the end of meiosis I, the primary oocyte divides into two cells: one secondary oocyte and one polar body. The polar body generally does not contribute to reproduction and usually degenerates. The secondary oocyte then completes meiosis II, but this division is asymmetrical, resulting in one functional egg cell and another polar body. Again, the polar body from meiosis II typically degenerates.

Therefore, from one primary oocyte that completes meiosis, there is one functional egg cell produced. The polar bodies are not functional for fertilization and ultimately do not contribute to reproductive potential. This process ensures that the resulting egg cell is as large as possible, containing the necessary cytoplasm and organelles to support early development after fertilization.