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2015 Mitosis


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Mitosis, basic

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2015 Mitosis

  1. 1. Cell Division
  2. 2. The Basics Who: Mitosis What: Cell division When: New cells are needed Where: Somatic cells (body cells) Why: Growth
  3. 3. The Basics Who: Somatic cells (Normal cells like in your toes) What: Cellular reproduction for growth, the cell cycle Where: Happens in somatic cells, regular body cells like in your toes Why: For growth (baby to adult) and to replace damaged cells (heal a cut) How: Duplicate cell parts making an exact copy of cell; one "mother" cell becomes two identical "daughter" cells. Remember: Toes as is mi-toes-is (mitosis)
  4. 4. Mitosis
  5. 5. Mitosis & Chromosomes Mitosis is the duplication of chromosomes
  6. 6. Chromosomes are made of DNA
  7. 7. Genes are part of Chromosomes
  8. 8. Cell Division • One parent cell becomes two daughter cells. • Happens in somatic cells, every day cells in the body • For growth StartStart FinishFinish 1 cell 2 cells
  9. 9. Cell Plate (Plants)
  10. 10. Mitosis in an animal cell • 1 cell to 4 cells
  11. 11. Uneven Division Division of cytoplasm is not always even
  12. 12. The Phases There are five phases
  13. 13. Cell Cycle
  14. 14. A. Interphase Inter = in between Actual Phases 1.Prophase Pro = first 2.Prometaphase Between First & Middle 3.Metaphase Meta = middle •Anaphase Ana = away •Telophase T All the phases 1 2 3 4 A 5 B
  15. 15. Mitosis with emphasis on metaphase
  16. 16. Mitosis Onion Root Tip
  17. 17. Interphase • Interphase is NOT a part of mitosis. • Interphase the cell grows before the DNA is duplicated, then DNA is duplicated, and lastly, prepares for division.
  18. 18. Prophase • During prophase, the DNA and proteins start to condense. • The microtubles are assembled start moving to one of the two centriole pairs toward the opposite end of the cell. Dark region = condensing chromatin Onion root tip image
  19. 19. Prometaphase • Sometimes considered part of the prophase. • Nuclear membrane disintegrates • Centrioles reach the poles of the cell • Chromosomes continue to contract. • Proteins attach to the centromeres. • The chromosomes begin moving. Dark region = condensing chromatin, animal cell
  20. 20. Metaphase • During metaphase, the microtubules penetrate nuclear region forming a spindle apparatus. • They attach to sister chromatids of each chromosome. • All chromosomes line up at spindle equator. • Now in their most tightly condensed form.
  21. 21. Anaphase • During anaphase, attachments between the two sister chromatids of each chromosome break. • Now separate chromosomes move to opposite spindle poles. Mid Anaphase Onion root tip
  22. 22. Telophase • Lastly, in telophase, the chromosomes decondense, texture of chromatin loosens. • New patches of membrane fuse to form new nuclear envelopes around them.
  23. 23. Cytokinesis & Daughter Cells Animal cells. •Pinching of cytoplasm into two cells. Plant cells •Cell plate forms between the two “new” cells. After cytokinesis •Cells now in interphase Called daughter cells. •Cells diploid, two each type of chromosome – same as parent cell's nucleus.
  24. 24. Mitosis on the run
  25. 25. Stages 1. Interphase Thecell isengagedinmetabolicactivityandpreparingformitosis(thenextfourphasesthatleaduptoandinclude nucleardivision). Chromosomesarenotclearlydiscernedinthenucleus,althougha darkspotcalledthenucleolusmaybevisible.Thecellmaycontaina pairofcentrioles(or microtubule organizingcentersinplants)bothofwhichareorganizational sitesformicrotubules.Thisisthe longest stage. 2. Prophase Chromatin in the nucleus begins to condense and becomes visible in the light microscope as chromosomes. The nucleolus disappears. Centrioles begin moving to opposite ends of the cell and fibers extend from the centromeres. Some fibers cross the cell to form the mitotic spindle. 3.
  26. 26. Stages 3. Prometaphase Sometimes considered part of the prophase. When the nuclear membrane disintegrates, the centrioles reach the poles of the cell, and the chromosomes continue to contract. Proteins attach to the centromeres. The chromosomes begin moving. 4. Metaphase Spindle fibers align the chromosomes along the middle of the cell nucleus. This line is referred to as the metaphase plate. This organization helps to ensure that in the next phase, when the chromosomes are separated, each new nucleus will receive one copy of each chromosome
  27. 27. Stages 5. Anaphase The paired chromosomes separate at the kinetochores and move to opposite sides of the cell. Motion results from a combination of kinetochore movement along the spindle microtubules and through the physical interaction of polar microtubules. 6. Telophase Chromatids arrive at opposite poles of cell, and new membranes form around the daughter nuclei. The chromosomes disperse and are no longer visible under the light microscope. The spindle fibers disperse, and cytokinesis or the partitioning of the cell may also begin during this stage. 7. Cytokinesis In animal cells, cytokinesis results when a fiber ring composed of a protein called actin around the center of the cell contracts pinching the cell into two daughter cells, each with one nucleus. In plant cells, the rigid wall requires that a cell plate be synthesized between the two daughter cells.
  28. 28. Interphase
  29. 29. Prophase
  30. 30. Prometaphase
  31. 31. Metaphase
  32. 32. Early Anaphase
  33. 33. Late Anaphase
  34. 34. Telophase
  35. 35. Daughter Cells
  36. 36. Mitosis
  37. 37. Can you identify the stages? 1. Are these plant or animal cells? 2. How can you tell? 3 4 5
  38. 38. Can you identify the stages? 6. Are these plant or animal cells? 7. How can you tell? 8 10 9
  39. 39. Purpose of Mitosis • Increase the size of an organism. • Replace worn out cells or repair damaged tissue. • Reproduce identical organisms, or clones.
  40. 40. Comparing Mitosis & Meiosis • Mitosis – Happens in somatic cells, every day cells in the body – For growth – Think: toestoes as is mi-as is mi- toestoes-is-is • Meiosis – Happens in sex cells (pre-embryonic cells) – For sexual reproduction – Think: e as in sex as in meiosis
  41. 41. Bibliography •Bio Review Cell Division •Access Excellence at the National Health Museum About Biotech •About •“The Cell Cycle & Mitosis Tutorial” The Biology Project University of Arizona • Mitosis •eMuseum Minnesota State University .html •Molecular Expressions •Universlity of North Carolina at Charlotte