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Cell Reproduction

Cell Reproduction

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Cell Reproduction

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  1. Cell Reproduction Mitosis & Meiosis

  2. http://biotech-adventure.okstate.edu/low/basics/mitosis/mitosis-diagram/diagram.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/mitosis-diagram/diagram.gif

  3. Cell Cycle http://www.bmb.psu.edu/courses/biotc489/notes/cycle.jpg

  4. Mitosis • One type of cell division Cell process in which the nucleus divides to form two nuclei identical to each other, and identical to the original nucleus, in a series of steps (prophase, metaphase, anaphase, and telophase)

  5. Mitosis allows for growth and replaces worn out or damaged cells.

  6. Interphase • Period of growth & development • Hereditary information (DNA) copied (replicated / duplicated) • Cells that do not divide (nerves) are always in interphase

  7. http://biotech-adventure.okstate.edu/low/basics/mitosis/phases/interphase/interphase.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/phases/interphase/interphase.gif

  8. Prophase • DNA begins to shorten & thicken • Now called chromatids / chromosomes • Centromeres form • Nuclear membrane breaks apart • Spindle fibers form

  9. http://biotech-adventure.okstate.edu/low/basics/mitosis/phases/prophase/prophase.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/phases/prophase/prophase.gif

  10. Metaphase • Chromatids / chromosomes line up • Centromere attaches to spindle fibers

  11. http://biotech-adventure.okstate.edu/low/basics/mitosis/phases/metaphase/metaphase.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/phases/metaphase/metaphase.gif

  12. Anaphase • Centromeres divide • Spindle fibers shorten • Chromatid pairs separate – move to ends of cell • Chromatids are now called • Each ½ of the pair is now called a chromosome

  13. http://biotech-adventure.okstate.edu/low/basics/mitosis/phases/anaphase/anaphase.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/phases/anaphase/anaphase.gif

  14. Telophase • Spindle fibers disappear • Chromosomes uncoil • Nuclear membrane forms • Cell divides (cytokinesis)

  15. http://biotech-adventure.okstate.edu/low/basics/mitosis/phases/telophase/telophase.gifhttp://biotech-adventure.okstate.edu/low/basics/mitosis/phases/telophase/telophase.gif

  16. http://biology.nebrwesleyan.edu/benham/mitosis/

  17. Mitosis Animation http://www.johnkyrk.com/mitosis.html

  18. Results of Mitosis • Division of nucleus • Nuclei are identical to each other • Same number & type of chromosomes

  19. Asexual Reproduction A type of reproduction - fission, budding, and regeneration - in which a new organism is produced from one parent and has DNA identical to the parent organism.

  20. Asexual Reproduction • Offspring produced from one organism • Hereditary information is identical • Mitosis is one form of asexual reproduction

  21. Sexual Reproduction Meiosis

  22. Sexual Reproduction A type of reproduction in which two sex cells, usually an egg and a sperm, join to form a zygote, which will develop into a new organism with a unique identity.

  23. Sexual reproduction results in a great variety, or diversity, of offspring.

  24. Meiosis • The nucleus divides twice • Meiosis I • Meiosis II

  25. http://biotech-adventure.okstate.edu/low/basics/meiosis/diagram/http://biotech-adventure.okstate.edu/low/basics/meiosis/diagram/

  26. Interphase • DNA is duplicated

  27. Prophase I • DNA shorten & thicken • Forms chromatids / chromosomes

  28. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/prophase/leptotene/leptotene.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/prophase/leptotene/leptotene.gif

  29. Metaphase I • Copied chromatids / chromosomes line up in middle of cell • Centromeres attach to spindle fibers

  30. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/metaphase-I/metaphase-I.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/metaphase-I/metaphase-I.gif

  31. Anaphase I • Chromatid pairs are pulled apart • They DO NOT separate • Move to ends of cell

  32. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/anaphase-I/anaphase-i.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/anaphase-I/anaphase-i.gif

  33. Telophase I • Cell divides • No further replication of hereditary material

  34. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/telophase-I/telophase-I.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/telophase-I/telophase-I.gif

  35. There are now two cells. Both cells have full sets of genetic material (chromosomes)

  36. Prophase II • Similar to mitosis • Starts with TWO cells instead of one • Spindle fibers appear

  37. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/prophase-II/prophase-II.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/prophase-II/prophase-II.gif

  38. Metaphase II • Duplicated chromatid / chromosomes line up in middle of cell • Spindle fibers attach to centromeres

  39. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/metaphase-II/metaphase-II.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/metaphase-II/metaphase-II.gif

  40. Anaphase II • Centromere divides • Chromatids separate & move to ends of cell • Chromatids are now individual chromosomes

  41. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/anaphase-II/anaphase-II.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/anaphase-II/anaphase-II.gif

  42. Telophase II • Spindle fibers disappear • Nuclear membranes form at each end of cell • Cells divide • Results in 4 cells • Each with ½ the original number of chromosomes

  43. http://biotech-adventure.okstate.edu/low/basics/meiosis/phases/telophase-II/telophase-II.gifhttp://biotech-adventure.okstate.edu/low/basics/meiosis/phases/telophase-II/telophase-II.gif

  44. Meiosis Animation http://www.johnkyrk.com/meiosis.html

  45. In summary:Meiosis • Two cells form during meiosis I • In meiosis II, both of these cells form two cells • The two divisions of the nucleus result in four sex cells (gametes) • Each has one-half the number of chromosomes in its nucleus that was in the original nucleus