Meiosis is a reduction division that produces haploid (n) gametes with half the chromosomes as seen in a diploid (2n) body cell. Meiosis occurs in the gonads or sex organs and produces gametes or sex cells. In sexually reproducing organisms, it is the fusion of the sperm nucleus which is haploid and the egg nucleus which is also haploid that will produce a diploid fertilized egg or zygote.
To observe an example of the ending number of chromosomes after meiosis we can use the chromosome number of 46 which is the diploid number found in human body cells. After meiosis occurs in the male or female gonads, the resulting four cells will be haploid and have 23 chromosomes each.
In spermatogenesis, one testis cell gives rise to four haploid sperm cells with 23 chromosomes in each. In oogenesis, one ovary cell gives rise to one ovum with 23 chromosomes, and three polar bodies, each with 23 chromosomes.
To conclude, meiotic division results in cells with the haploid number of chromosomes which become gametes to be used during sexual reproduction.
I have included a link with a diagram comparing oogenesis and spermatogenesis.
No comments:
Post a Comment