Meiosis
Introduction
Meiosis is a special type of cell division in which the number of chromosomes in daughter cells is reduced to half, as compared to the parent cell. It takes place in diploid cells only, in animals at the time of gamete production while in plants when spores are produced .There are two meiotic divisions. The first meiotic division is the reduction division whereas the second meiotic division is just like mitosis .
Meiosis I
It is divided into many sub divisions:
• Prophase I
• Metaphase I
• Anaphase I
• Telophase I
• Prophase I
This is very prolonged phase , and it is different from the prophase of mitosis because in this chromosomes behave as homologous pairs. Each diploid cell has two chromosomes of each type, oe member from each parent , because of fusion of male and female gametes .Each chromosome has two chromatids, because chromosomes have been replicated during interphase. Prophase 1 further consist of following stages :
1. Leptotene
The chromosomes became visible, shorten and thick. The size of the nucleus increases and homologous chromosomes start getting closer to each other
2. Zygotene
Synapsis starts during this phase . this pairing is highly specific and exactly pointed . Each
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It is a continuous process in which replication of genetic material took place in parent cells which is equally distributed into two daughter cells. The genetic material is composed of chromosomes. The process of mitosis begins when the chromosomes condense. The chromosomes align themselves. . Nuclear membrane forms around the separate daughter chromosomes. This process is known is called as Karyokinesis. In animal cells, the cleavage furrow deepens which eventually pinches the cytoplasm into two. In plant cells, the daughter cells develop a new cell wall. The parent cell split in half. This process is known as