1. Meiosis Sexual Reproduction

2. Why is meiosis important? Make eggs and sperm for reproduction Genetic diversity – half DNA from father and half from mother= new combination

3. Somatic cells – (any cell other than egg or sperm)-formed from mitosis only - – Have 46 chromosomes and divide to make identical cells with 46 chromosomes – Diploid (2n) Gametes (egg and sperm) – formed from meiosis only – Have 23 chromosomes – Haploid (n)

4. Autosomes are the 22 pairs (44) of chromosomes that are not involved in determining gender Sex chromosomes are the pair (2) that determine gender

5. Homologous chromosomes- pair of chromosomes that are similar in size, shape, and genetic content- one in each pair comes from the father and the other from the mother. Humans have ____pairs of homologous chromosomes.

6. Chromosome Numbers in Cells Diploid (2n) cell contains 2 sets of chromosomes (somatic cell) Haploid (n) cell contains 1 set of chromosome (gamete) What happens when 2 haploid cells fuse in fertilization?

8. Homologous Chromosomes and Sister chromatids

9. Mitosis vs Meiosis Mitosis – used for Growth – Two daughter cells – genetically identical to parent cell – two full sets of chromosomes (diploid) – makes bigger organism Meiosis – used for Reproduction – Four daughter cells – genetically different from parent cell (and each other) – one full sets of chromosomes (haploid) – helps makes another organism (sexual reproduction)

10. Meiosis- two cell divisions Meiosis preceded by an interphase (just like mitosis) – chromosomes replicated during the S phase.

12. Meiosis 1

13. Stages of Meiosis

15. Crossing Over in Action

17. How does this differ from metaphase in mitosis?

18. Independent Assortment

21. After the 1 st Division

27. http://highered.mcgraw- hill.com/sites/0072495855/student_view0/ch apter28/animation__unique_features_of_mei osis.html http://highered.mcgraw- hill.com/sites/0072495855/student_view0/ch apter28/animation__unique_features_of_mei osis.html Features unique to meiosis

28. Mitosis versus Meiosis

29. What happens to the possible combinations when crossing over occurs?

30. Sperm versus the Egg