Question

Explain the complicated and longest phase of cell division seen in germ cells.

Answer 1

The longest phase of cell division taking place in germ cells is meiosis.

Meiosis is a type of cell division taking place only in germ cells where the daughter cells will have half the number of chromosomes of parent cells.

The first meiotic division or Meiosis I takes place when the primary oocyte (2n) in case of oogenesis or primary spermatocye (2n) in case of spermatogenesis divide to form secondary oocyte and secondary spermatocytes which are haploid (n) and have half the number of chromosomes as in primary cells.

In oogenesis first polar body is formed.

After this process, second meiotic division or Meiosis II takes place which is similar to mitosis and gives rise to two gametes from each secondary cells which will have same number of chromosomes as in that of the secondary cells. An ootid and a second polar body are formed from secondary oocytes and 4 spermatids are formed from two secondary spermatids in spermatogenesis. The ootids differentiate into ovum and spermatids differentiate into sperms.