1. Meiosis Division of sex cells

2. Meiosis Cell Division to make 4 new, genetically different sex cells.

3. Gametes = Sex Cells Sperm (male) Egg (female)

4. Gametes Haploid (n) = ½ the number of chromosomes Important for fertilization –Egg + Sperm = Baby –½ + ½ = 1 full set of chromosomes

5. Somatic Cells = Body Cells Diploid (2n) = Full set of chromosomes –½ from Mom –½ from Dad

6. Human Gamete = Haploid = 23 chromosomes Human Somatic Cell = Diploid = 46 chromosomes

7. Stages of Meiosis Meiosis can be thought of as mitosis twice –Meiosis I: Separation of Homologous Chromosomes –Meiosis II: Separation of Sister Chromatids

8. Meiosis I 1.Prophase I Crossing over occurs 2. Metaphase I 3.Anaphase I Homologous chromosomes separate 4.Telophase I Cytokinesis occurs

9. Crossing Over Interchanging of pieces of DNA Changes the chromosome!

10. Meiosis II 1.Prophase II 2.Metaphase II 3.Anaphase II Sister chromatids separate 4.Telophase II Cytokinesis occurs

11. End Product 4 Genetically Different Gametes

13. Meiosis Animation