Meiosis Division of gametes Mitosis Somatic cells body

Meiosis Division of gametes

Mitosis: Somatic cells (body cells): nearly all cells in the body are diploid (2 n) and have 2 sets of chromosomes – one set from each parent Mitosis: nucleus/cell division in somatic cells Results in 2 identical cells

Meiosis: Gametes (sex cells): reproductive cells (sperm and eggs) are haploid (n) and have 1 set of chromosomes Meiosis: nucleus/cell division in gametes, resulting in haploid cells – needed so that when the gametes join together during fertilization the zygote created is diploid Results in four non-identical haploid daughter cells

Homologous Chromosomes homologous chromosomes: chromosomes that have genes for the same traits – one comes from each parent

Meiosis I: the first division in meiosis Prophase I: similar to prophase in mitosis Metaphase I: the homologous chromosomes line up at the equator Anaphase I: the homologous chromosomes separate to opposite poles Telophase I: similar to telophase in mitosis (results in 2 haploid nuclei)

Crossing Over During meiosis I, when homologous chromosomes form a tetrad, crossing over can occur. Genetic info is exchanged between homologous chromosomes

Meiosis II: the 2 daughter cells go through a second division (PMAT II), resulting in 4 haploid, non-identical daughter cells total.

Gametogenesis

Extra video on meiosis https: //www. youtube. com/watch? v=to. WK 0 f. Iy. F l. Y