Meiosis

This week in AP Biology we discussed about meiosis. Meiosis is a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in production of gametes and plant spores. Meiosis has two cell divisions, Meiosis I and Meiosis II. Meiosis I halves the number of chromosomes, while in Meiosis II, sister chromotids split.  Just like mitosis, meiosis goes through Prophase, Metaphase, Anaphase, Telophase, and Cytokensis, but these phases produce gametes and to simply make you, you. In Interphase I, DNA replicates and each chromosome becomes doubled.In Prophase I, crossing over occurs which makes two homolougous chromosomes line up next to each other. Once crossing over occurs, the chromosomes are no longer identical. In Metaphase I, homologous chromosomes line up along the equator of the cell. In Anaphase I, chromosomes pull apart from opposite ends of the cell. In Telophase I, the spindle fibers disintegrate and cytokinesis begins. Once cytokinesis is complete, Meiosis II begins. Meiosis II is very similar to mitosis. In Prophase II, the spindle fibers start to form. In metaphase II The chromosomes line up and each cell has only one of each homologous chromosome. In anaphase II, the sister chromotids move away from each other and in telophase II and cytokinesis, the formation of four genetically different haploid cells form.