Mitosis and Meiosis

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Mitosis and Meiosis

• By Andrew Stone
• Period 2

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Life Science Topic

• Compare sexual reproduction (offspring inherit
  half of their genes from each parent) with
  asexual reproduction (offspring is an identical
  copy of the parent cell).

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What is Mitosis?

• The process by which one copy of a parent cells
  DNA is copied into each of the 2 identical
  daughter cells.

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How it happens?

• The parent cells chromosomes double and then
  divide into each of the 2 identical daughter cells

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Stages of Mitosis

• Interphase
• Spends most of cell life in this phase.
• Cell prepare for division in this phase.

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Prophase

• chromatin condenses into chromosomes.
• The nuclear envelope breaks down
• spindles form at opposite ends of the cell.

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Metaphase

• the spindle fully develops and the chromosomes
  align at the middle of spindle fibers

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Anaphase

• In anaphase, the paired chromosomes separate and
  begin moving to opposite ends of the cell.
  Spindle fibers not connected to chromatids
  lengthen and elongate the cell. At the end of
  anaphase, each pole contains a complete set of
  chromosomes.

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Telophase

• The cell continues to lengthen.
• Nuclei begin to form at opposite ends.
• The nuclear envelopes of these nuclei are formed
• Nucleoli also reappear.
• Chromatin fibers of chromosomes uncoil.

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Cytokinesis

• During cytokinesis, the cytoplasm of a cell is
  physically divided to form two daughter cells
• The binding of some molecules or organelles to
  the chromosomes or spindle fibers ensures that
  each daughter cell will receive a fair share of
  components.

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Mitosis Links

• Mitosis and Cytokinesis
• Meiosis Animation

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What is Meiosis?

• Not to be confused with mitosis
• The process by which the number of chromosomes is
  reduced by half to form sex cells (sperm and egg)

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Why?

• Sex cells have half the chromosomes that body
  cells have so that when the sperm and the egg
  combine in the zygote, the zygote will have the
  right number of chromosomes.

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How?

• The double in the parent cell then the parent
  cell divides just like in mitosis except twice to
  produce 4 sex cells

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• The stages of meiosis are similar to those of
  mitosis except there are extra stages for the
  second division and in prophase some chromosomes
  swap genes
• The next slide shows 2 diagrams of the mechanics
  of meiosis and the stages of meiosis

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(No Transcript)
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Meiosis Links

• Interactive activity
• Meiosis Matching

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Recommended Extra Activities

• Read All about Mitosis and Meiosis by Elizabeth
  R. C. Cregan
• Also, try one of these fun activities

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• Paraphased By Andrew Stone
•  
•  
• 1.Newspaper article Write an article from the
  point of view of a person living during the
  discoveries of mitosis and meiosis. Answer the
  who, what, when, where and why questions. Your
  article must be supported by pictures with
  captions.
•  
• 2. Poem or song Write an original poem or song
  explaining the steps of mitosis and meiosis.
• 3. Create a model of both mitosis and meiosis
  Demonstrate the steps of mitosis and meiosis by
  creating a model of these processes. The model
  must be accurate, demonstrate knowledge, and be a
  creative design. It must be 3D .
•  
• 4. Write a childrens storybook Write an
  original story explaining the steps of mitosis
  and meiosis. The story must include all the parts
  of a story including characters, plot, dialogue,
  descriptions and illustrations.
• 5. Political cartoon You must create a
  political cartoon strip showing the steps of
  mitosis and meiosis. The cartoon must include
  colored drawings and captions.
•  
• 6. Animated FlipBook You must create a flip
  book depicting mitosis and meiosis that will show
  the stages of each process when flipped. Each
  page must have a picture (colored), as well as a
  description of what is happening. At the end of
  the book, you must write a comparison and
  contrast of the two processes.
•  
• Sources Pebble Brook High School Web Site

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Sources

• Ask.About.comBiology
• Encyclopedia.com
• Picsearch
• You Tube
• Cells Alive
• Clip Art
• THE END!