Question

What is the necessity of meiosis 2 in spermetogenesis?

Answer 1

Wow Nice Question

I haven't thought about it. Thank you for such a good question.

When primary spermatocytes are starting to undergo Meiosis There are 46 chromosomes and each chromosomes contain a pair of chromatids(these are duplicated in S phase of prophase. Here 2 DNA molecules unlike one in other cells are attatched to a centromere).
The primary spermatocyte undergo reduction division and the homologous chromosomes undergo seperation and form haploid secondary spermatocytes. Eventhough each are haploid the each 23 chromosome contains 2 chromatids that is 2 DNA molecules.

These chromatids should be separated. 2 chromatids in a chromosome cannot exist. In Meiosis 2 the chromatid seperate across the centromere and each one goes to seperate spermatids.

If meiosis 2 does not happen then the cell would contain 23 chromosome and 46 chromatids i.e 46 dna molecule unlike 23 chromosome and 23 chromatids seen in haploid cells.