Question

Identify the labels in the given diagram.

• A. P- Oogonia, Q- Primary oocyte, R- First polar body,
• B. P- Oocyte, Q- Oogonia, R- Second polar body, S- Ovum
• C. P- Primary oocyte, Q- Secondary oocyte, R- First polar body, S- Ovum
• D. P- Primary oocyte, Q- Oogonia, R- Secondary oocyte, S- Polar body

Answer 1

The correct option is C P- Primary oocyte, Q- Secondary oocyte, R- First polar body, S- Ovum

The figure represents the process of oogenesis. Oogenesis begins during fetal development in female. The primary oocytes (2n) in female ovaries begin their meiosis but become arrested in the diplotene stage of prophase I of meiosis I. When a female hits puberty these arrested primary oocytes (2n) restart meiosis I to form large secondary oocyte (n) and small first polar body(n). Meiosis I is followed by meiosis II. When a female ovulates, the secondary oocyte is in metaphase II. It then completes the second phase of meiosis to make a mature ovum only if fertilisation occurs.