Number of Ova from One Primary Oocyte

How many ova are produced from one primary oocyte?

Correct Answer: 1

Only 1 functional ovum is produced from one primary oocyte. The meiotic divisions are unequal — while the genetic material divides equally, the cytoplasm is retained in one large cell (the ovum), and the other products become non-functional polar bodies.

Pathway of Oogenesis

• 1 Primary oocyte (2n) → Meiosis I (unequal) → 1 Secondary oocyte (n) + 1st Polar body (n)
• 1 Secondary oocyte → Meiosis II (unequal, triggered by fertilization) → 1 Ovum (n) + 2nd Polar body (n)
• 1st Polar body may divide into 2 polar bodies
• Net result: 1 Primary oocyte → 1 ovum + 3 polar bodies

Why Only 1 Ovum?

The asymmetric division conserves nutrients/cytoplasm in the ovum for embryo development. Polar bodies are anucleate remnants with minimal cytoplasm that degenerate.