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Mitosis

Mitosis. What is it? Why is it Important? What do I need to know?. Why more cells?. Populations of single-cell critters Multicellularity? We all start out as a single cell…? The zygote… & become/remain multicellular. Binary Fission…Monera. Binary Fission..DNA duplicates…why?.

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Mitosis

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  1. Mitosis • What is it? • Why is it Important? • What do I need to know?

  2. Why more cells? • Populations of single-cell critters • Multicellularity? • We all start out as a single cell…? • The zygote… • & become/remain multicellular

  3. Binary Fission…Monera

  4. Binary Fission..DNA duplicates…why?

  5. DNA separates & new cell wall divides cell in two

  6. 2 ‘new’ cells…identical?

  7. Binary Fission

  8. quiz • What happens to the size of bacteria after binary fission? • What has to happen before fission occurs? • What benefit(s) do bacteria derive from binary fission (as opposed to sexual reproduction)?

  9. Eukaryotic cells?? • The nucleus? • Nuclear membrane • Chromosomes…not chromosome…? • All that ‘stuff’ in the cytoplasm?

  10. Eukaryotic cell cycle • Cell is ‘born’ • Duplicates DNA?? • Grows to…size? • Prepares to divide • Divides=mitosis

  11. Control of mitosis:CYCLIN

  12. The nuclelus must first divide before the cell can • Why? • How? • How much time of the cell cycle/life can be spent in mitosis?

  13. Chromosomes duplicate

  14. Kinetochore (centromere)

  15. plant cytokinesis

  16. Mitosis produces identical offspring (2N---2N)

  17. Why some cells stop mitosis…differentiation • Muscle cells… • Nerve cells… • Critical functions might be disrupted • Adaptations to this condition

  18. Importance??? • Growth • Replacement • Cancer • Regeneration of…

  19. Cancer? • Unregulated mitosis • Benign • Malignant/ metastasis • How does it begin?

  20. Normal cycle controls • Internal signals • External signals: growth factors fibronectin,etc carcinogens • Apoptosis • Immune functions • And…

  21. Cell immortilization!! • Hayflick limit?? • Hela cells • Contact inhibition • Increased telomerase activity • = immortalization!

  22. Immortalization??? • If you replaced… • Why not??…look at your shoestrings? • Telomerase & telomeres & …? • Recently… • Implications???

  23. Mitosis quiz • Use two words to describe the importance of mitosis • Draw and label the cell cycle…include G1, S, G2, M and cytokinesis…what happens at each stage? • Why might telomerase be important? • What disease is associated with mitosis? • Are all organisms limited to 50 mitotic divisions?

  24. Name stage of mitosis

  25. Name stage of mitosis

  26. Name stage of mitosis

  27. Name stage of mitosis

  28. Name stage of mitosis

  29. Name stage of mitosis

  30. Name stage of mitosis

  31. Name stage of mitosis

  32. These are bacteria • Watch the clip • What kind of reproduction is shown here? • What advantage does this confer on the organism?

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