Meiosis - Meiosis Meiosis is a form of cell division that...

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Meiosis Meiosis is a form of cell division that halves the number of chromosomes when forming specialized reproductive cells, such as gametes or spores. Meiosis involves two divisions of the nucleus- meiosis 1 and meiosis 2. Before meiosis begins, the DNA in the original cell is replicated. Thus, meiosis starts with homologous chromosomes. Homologous chromosomes are similar in size, shape, and genetic content. Stages of Meiosis 1. Prophase 1 The homologous chromosomes become visible, and the nuclear envelope breaks down. Crossing-over occurs when portions of a chromatid on one homologous chromosome are broken and exchanged with the corresponding chromatid portions of the other homologous chromosome. 2. Metaphase 1 The pairs of chromosomes are moved by the spindle to the equator of the cell. The homologous chromosomes remain together. 3. Anaphase 1 The chromosomes separate. As in mitosis, the chromosomes of each pair are pulled to opposite poles of the cell by the spindle fibers. But the
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This note was uploaded on 09/06/2011 for the course BIO 201 taught by Professor Mr.bajom during the Spring '09 term at Abu Dhabi University.

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Meiosis - Meiosis Meiosis is a form of cell division that...

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