3.2 Lecture 5: Meiosis-1
3.2.1 Lesson outline
D. The Phases of Meiosis
1. Meiosis involves two divisions of the nucleus and the cytoplasm. These divisions, known as meiosis I and meiosis II, result in four haploid cells.
2. During interphase, the reproductive cell grows and duplicates its chromosomes.
3. During meiosis I, each pair of duplicated homologous chromosomes separates.
4. After meiosis I, the two cells formed during this stage go through a second division of the nucleus and cytoplasm called meiosis II. During meiosis II, sister chromatids separate to produce four haploid cells.
E. Why is meiosis important?
1. Meiosis forms sex cells with the correct haploid number of chromosomes. This maintains the correct diploid number of chromosomes in organisms when sex cells join. Meiosis creates genetic variation by producing haploid cells.