Question 1
When a female ovulates, in what phase of division is the oocyte?
- Metaphase II
- Metaphase I
- Prophase II
- Prophase I
- Anaphase I
Explanation: When a female ovulates, the oocyte is in metaphase II, until it becomes fertilized by a sperm. It then completes the second phase of meiosis to make a mature ovum. Remember that, unlike spermatogenesis, oogenesis begins during development. All oocytes undergo meiosis I during fetal development, and are kept suspended in prophase II until ovulation, when they shift to metaphase II. Meiosis only continues beyond metapahse II if fertilization occurs.