Question

How do spermatogenesis and oogenesis differ in terms of the number of gametes they produce? A. Spermatogenesis produces four functioning gametes, and oogenesis produces one large gamete with three polar bodies. B. Spermatogenesis produces one large gamete with three polar bodies, and oogenesis produces four functioning gametes. C. Spermatogenesis produces two functioning gametes with two polar bodies, and oogenesis produces four large gametes.

Answer 1

Spermatogenesis produces four functioning gametes, and oogenesis produces one large gamete with three polar bodies. Statement A is correct. In spermatogenesis, all the four gametes are functional whereas in oogenesis only one large gamete serves as an ovum while other 3 degenerate and they are termed as polar bodies. During oogenesis, gamete production i.e. ovum production doesn't occur like spermatogenesis . During oogenesis, there arrives a stage when gamete production is halted at diplotene/diakinesis stage of meiosis - I and this is known as first meiotic arrest. During this process a polar body is generated. Thenafter, at the time of puberty meiosis resumes, but it is again arrested at meiosis -II stage. This is known as second meiotic arrest. This process is completed only when the sperm arrives and produces another polar body.