At what point does the secondary oocyte complete meiosis?
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Solution
Secondary oocyte:
The primary oocyte is formed from oogonia (gamete mother cells) during oogenesis.
Primary oocytes enter prophase-I of meiosis and remain dormant till puberty. They remain arrested at this stage due to the absence of luteinizing hormone (LH).
At the onset of puberty, the primary oocyte (2n) undergoes the first meiotic division. This results in the formation of the secondary oocyte (n).
Secondary oocytes start undergoing second meiotic division but get arrested at metaphase II; until they meet the sperm in the fallopian tube.
The secondary oocyte completes meiosis at the time of fertilization. After completing meiosis, the secondary oocyte gives rise to an ovum.