Respuesta :
During meiosis, two successive nuclear divisions happens namely Meiosis I or reduction and Meiosis II or division. In meiosis I, it separate chromosomes after allowing crossing over. In meiosis II, it the then separates each chromosomes by splitting them. This division produces 4 haploid cells.
Two cell divisions occur during meiosis.
Further Explanation:
Cell division is the phenomenon by which parental cells divide into new cells. There are two kinds of cell division, meiosis, and mitosis.
Meiosis mostly occurs in the gamete cells. In this division, parent cells segregate into four daughter cells. The numbers of chromosomes in new cells are different from parental cells. Daughter cells consist of half of the number of chromosomes as the parent cells, therefore, this division known as reductional division. Meiosis is divided into two stages meiosis-I and meiosis-II.
Meiosis-I
Prophase-I: In this stage paired chromosome condense and crossing over occur.
Metaphase-I: In this stage homologous pair lines up at the metaphase plate for separation.
Anaphase-I: The homologous chromosome is pulled apart and move apart to opposite poles with the sister chromatid intact.
Telophase I: The chromosomes appear at opposite poles of the cell. After this chromosome undergoes meiosis II.
Meiosis-II
1. Prophase-II: During this phase, the condensation of the chromosomes takes place and these chromosomes become visible. Spindle fibers formation takes place, breakdown of the nuclear envelope, and nucleolus disappear.
2. Metaphase-II: During this phase, the development of spindle fibers is completed and centrosomes are found at the opposite terminals of the cell. The chromosomes line up at the metaphase plate. Each of the sister chromatids is linked to the spindle fiber starting from the opposite poles.
3. Anaphase-II: During this phase, the cohesion proteins link with the sister chromatids and splits them down. The sister chromatids are pulled towards the opposite terminals of the cell and the non-kinetochore spindle fibers mainly lengthen and elongate the cell.
4. Telophase-II: During this last phase, the chromosomes arrive at the opposite terminals and start to decondense. The nuclear envelope reappears, and the mitotic spindle breaks down. This marks the end of the mitosis.
The end phase of the cell cycle is called cytokinesis wherein the cleavage furrow occurs are segregates the daughter cells. In-plant cells, the cell plate is responsible for the segregation of the daughter cells.
Learn more:
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Answer Details:
Grade: High School
Subject: Biology
Chapter: Cell Cycle
Keywords:
Mitosis, meiosis, cell division, anaphase, telophase, cytokinesis, prophase, metaphase, segregation, chromosome.
