Process of mitosis and meiosis : Introduction
Cells are the basic unit of life. To increase the number of cells, cell division is needed. There are two processes in cell division, mitosis and meiosis.
Mitosis 有絲分裂
Mitosis is involved in the development of an adult organism from a single fertilized egg, in growth and repair of tissues, regeneration of body parts and asexual reproduction.
There are 2 stages of mitosis, nuclear division and cytoplasmic division (cytokinesis) 胞質分裂. After each division, 2 identical daughter cells are formed.
Please see the following microscopic slide that shows onion root cells in different stages of mitosis. Note the appearance of chromosomes at each stage of mitosis.
Meiosis 減數分裂
Meiosis is involved in the production of gametes 配子 or spores that give rise to new individuals.
There are 2 divisions, first and second meiotic division, to form 4 haploid 單倍體 daughter cells from 1 parent diploid cell. The significance of meiosis is to produce gametes for sexual reproduction and provide genetic variations among the gametes after fertilization.
Please watch the following animation of meiosis and comment on the differences between mitosis and meiosis.