Meiosis. Before meiosis can happen, the DNA Must replicate, this is done in the stage of interphase. Following interphase the first stage of meiosis occur

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Meiosis essay

Meiosis is a reduction division which occurs in sexually reproducing organisms to produce gametes. It involves one division of the chromosomes followed by two divisions of the nucleus and cell. The diploid parent cell gives rise to four haploid daughter cells.

        Before meiosis can happen, the DNA Must replicate, this is done in the stage of interphase. Following interphase the first stage of meiosis occur, this is the reduction division and starts with prophase I. In early prophase I centrioles are at their respective poles and their spindle fibres start to grow. The chromosomes become more visible with a beaded appearance due to the centromeres. The chromosomes become more visible by coiling up and condensing. In mid prophase I the nucleolus had gone ant the chromosomes, which consist of two identical chromatids, come together in their bivalents. A bivalent is a pair of homologous chromosomes. Next in late prophase I the nuclear envelope disintegrates so the spindle fibres can attach to the centromeres. The chromosomes can now be seen as two chromatids. In this stage adjacent non-sister chromatids can cross over at the point of chiasma and exchange part of their genetic material.

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        The Next stage of Meiosis is metaphase I. The bivalents arrange themselves on the equator in a random assortment. This random assortment leads to genetic variation. The spindle fibres now attach to the centromeres.

        Anaphase I follows after metaphase. In anaphase I the chromosomes, as pairs of chromatids, are pulled to the opposite poles of the cell. Spindle fibres which are attached to the centromeres contract to pull the chromosomes to their poles.

        Telophase I now occurs. Cells divide by constriction which is also known as cytokinesis. The nucleolus reforms and the nuclear envelop also reforms. Now each cell has ...

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