2. Mitosis How do your cells divide? Ch. 6 and Ch. 7

3. Chromosome Talk

4. A few words before we start…..  Haploid: (n) 1 set of unpaired chromosomes  Diploid: (2n) 2 haploid sets of chromosomes (1 pair)

5. Why Do Cells Divide? Surface area Damaged cells Sex cells

6. Cell Reproduction is either sexual or asexual

7. Asexual Reproduction (one parent)  Binary Fission-  Budding  Vegetative Propagation  Regeneration

8. Advantages of Asexual Reproduction Speed Desirable Characteristics Replacement

9. DNA Structure Ch. 9  Made up of nucleotides  There are 3 parts to each nucleotide –Deoxyribose sugar –Phosphate group –One of 4 Nitrogen bases

10. A G G T C C Nucleotide Phosphate group Deoxyribose Sugar Nitrogen Base

11. Nitrogen Bases There are four possible nitrogen bases: Adenine (A)Thymine (T) Cytosine (C)Guanine (G) A G T C

12. Nitrogen Base Pairing These bases always pair together in DNA: Adenine (A)Thymine (T) Cytosine (C)Guanine (G) A G T C

13. DNA Replication  Before a cell can divide the DNA must replicate (make a copy of itself)

14. DNA Replication  Making a new strand of DNA is actually quite easy.  Replication occurs in 3 easy steps…

15. 1. DNA Unzips  An enzyme unzips the molecule  The enzymes breaks the hydrogen bonds that hold the nitrogen bases together.

16. A G G T C C DNA Replication DNA Unzips

17. A G G T C C

18. A G G T C C

19. A G G T C C

20. A G G T C C

21. A G G T C C Left Strand of Original DNA Right Strand of Original DNA

22. 2. Base Pairing  Complementary bases match with each DNA strand in the open helix

23. A G G T C C Left Strand Original DNA Right Strand Original DNA DNA Replication Base Pairing

24. A G G TT C C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand DNA Replication Base Pairing

25. A G G T C T C C Left Strand Original DNA Right Strand Original DNA New Right DNA Strand DNA Replication Base Pairing

26. Left Strand Original DNA Right Strand Original DNA New Right DNA Strand A G G T C C T C C DNA Replication Base Pairing

27. Left Strand Original DNA Right Strand Original DNA New Right DNA Strand A G G T C C T C C A New Left DNA Strand DNA Replication Base Pairing

28. Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand A G G T C C T C C A G DNA Replication Base Pairing

29. Left Strand Original DNA Right Strand Original DNA New Right DNA Strand New Left DNA Strand A G G T C C T C C A G G DNA Replication Base Pairing

30. 3. DNA Zips Up  An enzyme zips the new molecules back up.

31. DNA Replication  Voila!  Two identical strands of DNA! T C C A G G T C C A G G T C C A G G

32. DNA Replication Review Step 1 Step 2 Step 3

33. Remember - All this takes place in INTERPHASE G2G2

34. Now that DNA has replicated, we are ready to begin Mitosis (nucleus of the cell divides) T C C A G G T C C A G G

35. Parent Cell DNA condenses into chromosomes Chromosomes align on the equator Chromosomes separate DNA uncoils Prophase Metaphase Anaphase Telophase MITOSIS

36. Cytokinesis  Cleavage (indention in cell membrane) or cell plate formation occurs.  Cell divides. Animal Cell Plant Cell

37. The Cell Cycle

38. Mitosis Animation

39. Overview of the Cell Cycle PMAT

40. It’s all about the chromosomes! –There are 46 in human body cells –The number of chromosomes remain constant during Mitosis

41. Which Cells Go Through Mitosis? Growth Repair Work Cells which help the body in: The cells are called autosomes

42. What happens if cell division gets out of control ?  CANCER  The body doesn’t respond normally to the body’s control mechanisms  p. 127, 138-139

43. Bone Cancer X-ray Ovarian Cancer Cell Dividing

44. Skin Cancer

45. Mitosis Review 1. Is the beginning parent cell diploid or haploid (2n or n)? 2. Are the daughter cells diploid or haploid (2n or n)?

46. More Mitosis Review 3. How many daughter cells are produced? 4. Are the resulting daughter cells different from the parent cell?

47. More Mitosis Review 5. Are the resulting daughter cells different from each other? 6. How many chromosomes are in a human parent cell? 7. How many chromosomes are in a human daughter cell?

48. More Mitosis Review 8.What types of cells are produced by mitosis? 9. Why (when) does a cell go through mitosis?