Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction.
What is an egg in meiosis?
Oocytes, progenitor cells of eggs, are kept in ovaries where they are maintained in prophase of meiosis I. At this stage, recombined homologous chromosomes are held together in a bivalent structure inside the nucleus (Figure 1). … At this stage, the cell is called an egg and awaits fertilisation.
How is meiosis related to fertilization?
Meiosis is where a diploid cell gives rise to haploid cells, and fertilization is where two haploid cells (gametes) fuse to form a diploid zygote. … In this type of life cycle, the single-celled zygote is the only diploid cell.
What happens after meiosis is complete?
Following completion of oocyte meiosis, the fertilized egg (now called a zygote) contains two haploid nuclei (called pronuclei), one derived from each parent. In mammals, the two pronuclei then enter S phase and replicate their DNA as they migrate toward each other.
In what organs does meiosis take place?
Meiosis occurs in the testes of men and ovaries of women.
Why is meiosis 2 necessary?
The cells are diploid, therefore in order to distribute the chromosomes eqully among the daughter cells so that they contain half the chromosome , Meiosis II is necessary. … It reduces the chromosome number to half so that the process of fertilisation can restore the original number in the zygote.
In what way is meiosis II similar to mitosis?
The mechanics of meiosis II is similar to mitosis, except that each dividing cell has only one set of homologous chromosomes. Therefore, each cell has half the number of sister chromatids to separate out as a diploid cell undergoing mitosis.