2. Quick review: identify this stage of the diploid cell cycle.

9. Defined: Process where the chromosome number is reduced by half Gametes created (egg, sperm, pollen) End Result: Four Haploid Cells

10. Same process (G1, S, G2) –Chromatin duplicated

11. Synthesis (S stage)

12. Similar as mitosis, except… Two Events: –1) Synapsis: Pairing of homologous chromosomes –Dad’s #1 chromosome pairs with Mom’s #1, etc… –The four paired chromatids equals a TETRAD –2) Crossing Over: Exchange of genes

13. Early Prophase

14. Synapsis: Homologous chromosomes align

15. Homologous chromosomes (tetrads) align along cell equator

16. Homologous chromosomes are pulled apart to opposite ends –Tetrads separated

17. Cytokinesis divides the cells Each cell contains 1 of the homologous chromosomes (23 total)

18. Same as mitosis Note: No new DNA was created (no 2 nd interphase)

19. Remaining chromosomes are aligned at cell equator

20. Chromatids are pulled to opposite ends

21. Nucleus reforms on the four new cells Cytokinesis divides the cytoplasm Chromatids uncoil End Result: Four haploid cells

22. Defined: Production of sperm cells  in male testes Meiosis produces four haploid sperm cells at a time

23. Defined: Production of the egg cell (ovum) –In female ovaries During meiosis I: Cytoplasm distributed unequally After meiosis II: –1 cell matures –3 “Polar Bodies” dissolve

24. Division of somatic cells Ex: Blood cells, skin cells, nerve cells… End Result: 2 Diploid Cells Importance: Replaces aging cells Importance: Form of asexual reproduction Division of gametes Ex: Sperm and Egg cells End Result: 4 Haploid cells Importance: Reduces the gamete chromosome number by half

25. Kobe Kuiz 1) Name three ways that meiosis and mitosis differ. 2) Pick a stage of meiosis…any stage. Describe what happens in it. 3) What type of cells does meiosis create? 4) What are homologous chromosomes? 5) When do homologous chromosomes move to opposite ends of the cell? 6) When do chromatids move to opposite ends of the cell? 7) Why is no DNA created in meiosis 2? 8) How does meiosis differ in males vs. females?