Nuclear Divisions

There are two kinds of nuclear division. In mitosis, the daughter cells end up with exactly the same chromosome number as the parent cell - typically the diploid (2n) number - so mitosis is described as producing genetically identical, same-ploidy cells. It takes place whenever an organism needs to grow, replace worn-out or damaged cells, or reproduce asexually. In meiosis, by contrast, the daughter cells receive only half the chromosome number of the parent cell, ending up haploid (n); meiosis therefore only makes sense in cells destined to become gametes, because fusing two haploid gametes at fertilisation restores the full diploid number in the next generation. Whichever type of nuclear division (karyokinesis) occurs, it is normally followed by division of the cyto …