Question

Given below are few statements with reference to oogenesis in a human female:

• An unequal division of the primary oocyte forms a large secondary oocyte and a tiny first polar body.
• A couple of thousands of oogonia are formed within each fetal ovary during embryonic development.
• Primary oocytes start meiosis-I but it gets arrested temporarily at prophase-I during fetal development.
• Fertilisation induces the completion of the meiotic division of the secondary oocyte.
• A primary oocyte on meiosis forms an ovum and a polar body.

Choose the option with all true statements from the given options:

• A. (i), (ii), (iv)
• B. (ii), (iii), (v)
• C. (ii), (iv), (v)
• D. (i), (iii), (iv)

Hint:

During oogenesis, the primary oocyte is arrested in prophase-I and completes meiosis only upon fertilisation. Oogenesis involves unequal cell divisions producing polar bodies.

Answer 1

The Correct Option is D

(i) True – The primary oocyte undergoes asymmetric division to form a large secondary oocyte and a small polar body.
(ii) False – Millions (not just a couple of thousands) of oogonia are formed during fetal development.
(iii) True – Primary oocytes begin meiosis-I but are arrested in prophase-I until puberty.
(iv) True – Completion of meiosis-II in the secondary oocyte is triggered by fertilisation.
(v) False – The primary oocyte forms a secondary oocyte and a polar body; the ovum is only formed after fertilisation.