Student Goals

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Student Goals

• Explain the purpose of cell division
• Identify the steps and events of each cell phase.

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Cell Size

• Cell size is constrained by cellular needs for
  raw materials and the chemical properties of
  molecules.
• too big cant get enough matter and energy or
  get rid of chemical wastes
• too big too many demands on DNA things get
  out of control
• Sometimes, smaller is better

Which nucleus is bigger?
They are exactly the same size.
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Life of a Cell

• Cells lining the esophagus live for 2-3 days
• Cells lining the small intestine live 1-2 days
• White blood cells may live for only 10 hrs, or
  for decades
• Red blood cells live less than 120 days
• Muscle cells live for years
• Nerve cells live for many years

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Cell Life

• Most of the time that a cell is alive, it is busy
  growing, making molecules and using them.
• This is called Interphase (the time between
  mitotic divisions)
• The DNA is strung out in the nucleus, invisible.
  (chromatin)
• When the cell reaches its size limit, it gets
  ready to divide in two in a process called
  mitosis.
• Before that can happen, the DNA and all the
  cellular organelles are replicated during
  interphase.

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Life Cycle of a Cell

• Interphase growth, increase in size, and
  synthesis of organelles and molecules
• G1
• S
• G2
• Mitosis - Cell division
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis

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The Big Picture

• One cell becomes twoEach with the same number of
  chromosomes as the Parent cell

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The Big Picture- 2

• Before PROPHASE the chromatin is replicated
  (copied).
• During PROPHASE it condenses into chromosomes.
• Each chromosome has a replicated twin sister
  chromatids.
• These are the 46 chromosomes in a human cell as
  mitosis begins.

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Chromatin gt Chromosome gt Chromatids

• Chromatin, Chromosomes, and Chromatids are all
  the same named differently depending on the
  stage.

Chromatin Chromosome Chromatids
Differences between Chromatin/Chromosomes/Chromati
dshttp//www.youtube.com/watch?vs9HPNwXd9fk
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1. Prophase Pro pre (before) 2.
Metaphase Meta middle 3. Anaphase
Ana apart 4. Telophase Telo two 5.
Cytokinesis Cyto cell, kine move
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Mitosis What does it look like?
Identify each stage from the pictures
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Mitosis What does it look like?
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Mitosis What does it look like?
Examine Allium root tips under the microscope and
identify the parts.
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Mitosis What does it look like?
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Quiz yourself

• Check out this website! (biologycorner.com) For a
  REVIEW and practice quiz!
• http//www.biologycorner.com/bio1/cellcycle.html
• Practice Quiz on Discovery Education
• http//school.discoveryeducation.com/quizzes6/musk
  opf/mitosis1.html