1. Review: 1. What is mitosis? 2. What are the stages of mitosis? Process of Cell Division Prophase, Metaphase, Anaphase, Telophase

2. Review: 3. How many cells are created through this process? 4. What types of cells are made? 2 cells Identical Somatic Diploid cells

3. Today’s Target I can describe, draw, and explain the steps of how gametes (sex cells) are formed. I can explain how the daughter cells in meiosis are all different I can compare and contrast between somatic cells and gametes

4. INTERPHASE In nucleus

5. MITOSIS Begin with a Diploid Cell 2N = 4

6. MITOSIS Chromosomes are in a single file line

7. MITOSIS Centromere divides Sister chromatids move apart

8. MITOSIS End with two Diploid Cells that are identical

9. ◦Begin with 1 somatic Diploid (2N) cell MITOSIS ◦4 phases: ◦Prophase ◦Metaphase ◦Anaphase ◦Telophase ◦End with 2 Identical Diploid (2N) cells

10. Meiosis The process by which Gametes are formed Gamete: ◦Sperm or Egg ◦Haploid: One set of chromosomes ◦(Only mom or dad) ◦In eukaryotic cells, this means that gametes have HALF the number of chromosomes as Diploid cells

11. MEIOSIS

12. Homologous chromosomes form tetrads at the equator = pair of homologous chromosomes

13. MEIOSIS Homologous chromosomes move AWAY to the poles

14. MEIOSIS 2 cells so far

15. MEIOSIS

16. Chromosomes align at the equator NOW … single file line equator

17. MEIOSIS Centromeres divide

18. MEIOSIS End with 4 Haploid Cells All are different n = 2

19. 4 Sperm Cells

20. 1 Egg Cell

21. Meiosis Notes 1. Similar to Mitosis 2.Divides twice = Meiosis I : Meiosis II **** 8 phases total ****

22. Meiosis: Two Part Cell Division 22 Meiosis I Meiosis I Meiosis II Diploid Haploid

23. Meiosis… …Occurs in Sex Organs (ovaries and testes) … Produces 4 cells with half of the genetic material (Haploid cells)

24. Meiosis… …in Humans: Gametes = sperm (23) and egg (23) Zygote = fertilized egg (46)

25. Fertilization Gamete

26. Egg Haploid nucleus Fertilization Results In A Diploid Zygote Sperm Haploid nucleus

27. Sperm Fertilization Results In A Diploid Zygote Egg Haploid nucleus Haploid nucleus

28. Sperm Fertilization Results In A Diploid Zygote Egg Haploid nucleus Haploid nucleus

29. Sperm Fertilization Results In A Diploid Zygote Egg Haploid nucleus Haploid nucleus

30. From Zygote to Embryo Zygote 2n Zygote 2n

31. Homologous Chromosomes exchange DNA ◦Increases variation in a species ◦Occurs during Prophase I of Meiosis I Crossing Over

32. Crossing over Exchange of genes

33. MEIOSIS Homologous chromosomes move AWAY to the poles

34. Crossing Over

36. Homologous Chromosomes Match up the homologous chromosomes

37. Crossing Over Advantages - Genetic Variation - Higher survival rate in a changing environment

38. Mitosis Vs. Meiosis PROPHASEPROPHASE I

39. Mitosis Vs. Meiosis METAPHASEMETAPHASE I

40. Mitosis Vs. Meiosis ANAPHASEANAPHASE I

41. Mitosis Vs. Meiosis TELOPHASETELOPHASE I

42. Mitosis Vs. Meiosis CYTOKINESIS

43. Mitosis Vs. Meiosis PROPHASE II

44. Mitosis Vs. Meiosis METAPHASE II

45. Mitosis Vs. Meiosis ANAPHASE II

46. Mitosis Vs. Meiosis TELOPHASE II

47. Create a Venn diagram to compare and contrast MITOSIS MEIOSIS

48. Gametes Crossing over 2 cells 4 cells 1 cycle of PMAT 2 cycles of PMAT Haploid cells DNA replicated only once Cellular reproduction Genetically different cells Somatic cells sperm cells Interphase occurs before Sex cells 2N 46 chromosomes 23 chromosomes Asexual Sexual N Body Cells Cells are identical

49. Mitosis vs. MEIOSIS mitosis meiosis Somatic cells Cells are identical 2N 46 chromosomes Asexual Body cell 2 cells 1 cycle of PMAT Gametes Crossing Over 4 cells 2 cycles of PMAT Haploid Sex cells 23 chromosomes N Sperm cell sexual DNA replicates only once Cellular Reproduction Interphase occurs before

50. 12 24 yes no 4623 no yes 11

51. Half the number of chromosomes n2n Body Cell (somatic) Sex Cells (gametes) Both sets of chromosomes