The following points highlight the three main types of cell division in animals and plants. The types are: 1. Amitosis 2. Mitosis 3. Meiosis. Cell Division: Type # 1. Amitosis: The amitosis or direct cell division is the means of asexual reproduction in unicellular organisms like bacteria and protozoans and also a method of multiplication or growth in foetal membranes [...]
In this article we will discuss about the meiotic division of a cell. The meiotic division includes two complete divisions of a diploid cell resulting into four haploid nuclei. The first meiotic division includes a long prophase in which the homologous chromosomes become closely associated to each other and interchange of hereditary material takes place between them. Further, in the [...]
The following points highlight the three successive stages of oogenesis. The stages are: 1. Multiplication phase 2. Growth phase 3. Maturation phase. Oogenesis: Stage # 1. Multiplication Phase: The primordial germinal cells divide repeatedly to form the oogonia (Gr., oon = egg). The oogonia multiply by the mitotic divisions and form the primary oocytes which pass through the growth phase. [...]