2. CHAPTER 20 MITOSIS There is more to lectures than the power point slides! Engage your mind

3. The Cell Cycle - Mitosis

4. Where it all began… You started as a cell smaller than a period at the end of a sentence… Going from an egg to a baby…. the original fertilized egg has to divide… and divide…

6. One-celled organisms o For asexual reproduction (clones) o a = without Multi-celled organisms o for growth & development  from fertilized egg to adult o for repair & replacement  replace cells that die from normal wear & tear or from injury amoeba

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8. What has to be copied? o DNA o organelles o cell membrane o lots of other molecules  enzymes animal cell plant cell

9. A dividing cell duplicates its DNA o creates 2 copies of all DNA o separates the 2 copies to opposite ends of the cell o splits into 2 daughter cells But the DNA starts as a loosely wound in the nucleus If you tried to divide it like that, it could tangle & break nucleus cell DNA

10. nucleus cell DNA nucleus cell 4 chromosomes in this organism DNA in chromosomes in everyday “working” cell DNA in chromosomes in cell getting ready to divide DNA has been “wound up”

11. 46 chromosomes 23 pairs

12. 46 chromosomes 23 pairs

13. double-stranded human chromosomes ready for mitosis

14. nucleus cell DNA in chromosomes nucleus cell duplicated chromosomes chromosomes in cell 4 single-stranded chromosomes duplicated chromosomes 4 double-stranded chromosomes

15. Stage 1: cell copies DNA nucleus cell DNA Copy DNA! (interphase)

16. Stage 2: DNA winds into chromosomes o keeps it organized nucleus cell duplicated chromosomes like a Plate of spaghetti! (prophase)

17. Stage 3: Chromosomes line up o chromosomes line up in middle o attached to protein “cables” called Spindle Fibers that will help them move duplicated chromosomes lined up in middle of cell Meet in the Middle (metaphase)

18. Stage 4: Chromosomes separate o chromosomes split, separating pairs o start moving to opposite ends chromosomes split & move to opposite ends Pull APART (anaphase)

19. Stage 5: Cell starts to divide o cells start to divide o nucleus forms again Two Cells! (telophase)

20. Stage 6: DNA unwinds again o cells separate o now they can do their every day jobs (cytokinesis)

21. Get 2 exact copies of original cells

22. interphaseprophase metaphaseanaphasetelophase cytokinesis I.P.M.A.T.C. P lease M ake A nother T wo C ells