How do Organisms Reproduce? — Science STD 10 — Question

In both sexual and asexual reproduction, there is great importance of maintaining a constant number of chromosomes. But the process mechanism is dissimilar in both the type of reproductions.

1. In case of asexual reproduction, the entire set of chromosomes is replicated and transferred to the next generation. DNA copying is accompanied by the creation of an additional cellular material, after which the DNA copies separate, each with its own cellular apparatus. Effectively, a cell divides to give rise to two cells. Thus, chromosome number remains unchanged.

For example: Replica of Amoeba by binary fission.

2. In case of sexual reproduction, the chromosome number is halved to form gametes. Then these gametes combine to restore the original chromosome number.

For example: In the case of human beings they have 46 chromosomes present in a cell, during reproduction gametes are generated which include half the number i.e. 23. Now, when female gamete containing 23 chromosomes is combined with male gamete with 23 chromosomes, the number is restored to original 46 (23 + 23).