Mitosis and the Cell Cycle

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Mitosis and the Cell Cycle

• Cell Division

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CELL DIVISION

• FACT All cells come from preexisting cells.
• QUESTION How?
• ANSWER All cells come from preexisting cells
  through a process called cell division.

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CELL DIVISION

• FACT Life is perpetuated through cell division.
  Humans are made up of approximately 100 trillion
  cells but it all started with one single cell

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MITOSIS

• All cells alternate between two stages. Either
  they are dividing or not dividing. For most
  cells, the dividing phase is only a small part of
  the total life cycle.

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THE NOT DIVIDING STAGE

• When a cell is not dividing it is in a stage
  called INTERPHASE.
• During INTERPHASE, the cell takes in nutrients
  (like sugars) and produces building materials
  (like proteins). These materials are used by the
  cell for energy, growth, and repair of damaged
  parts.

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• After a period of rapid growth the cell prepares
  for the division phase by duplicating its
  chromosomes within the nucleus.
• After the genetic material is copied, there is
  another period of growth and preparation.

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THE DIVIDING STAGE

• Even though living things are diverse, most cells
  show remarkable similarities when it comes to
  cell division.
• In basic terms a single mother cell divides
  into two identical daughter cells.

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• The cell division phase has two components
• MITOSIS when the cell divides its nuclear
  material.
• CYTOKINESIS when the cell divides its cytoplasm
  and the contents in it.

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MITOSIS

• 1. INTERPHASE (not dividing)
• The cell grows and prepares for cell division by
  duplicating its genetic material. Another growth
  phase then readies the cell for the division.

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INTERPHASE
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2. PROPHASE

• The duplicated chromosomes become short and thick
  and are actually visible with a light microscope.
  The nuclear membrane begins to dissolve.

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PROPHASE
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3. METAPHASE

• The double stranded chromosome line up in the
  middle of the cell.
• There no longer is a nuclear membrane.

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METAPHASE
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4. ANAPHASE

• Each chromosome splits and the two halves begin
  to move to opposite poles of the cell.

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ANAPHASE
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5. TELOPHASE

• As the chromosomes reach the poles of the cell, a
  new nuclear membrane begins to form around each
  set. Cytokinesis begins the cytoplasm and
  organelles split into equal parts. The cell
  membrane starts to pinch together and two
  daughter cells are formed.

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TELOPHASE
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INTERPHASE (not dividing)

• The two new daughter cells begin growing and
  duplicating their genetic material.

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MITOSIS VIDEO CLIPS

• http//www.xvivo.net/press/harvard_university.htm
  (Scientific Animation of What Goes On Inside a
  Cell)
• http//www.ibiblio.org/virtualcell/tour/cell/cell_
  mem1.htm (Virtual Cell)
• http//www.cellsalive.com/cells/cell_model.htm
  (Cells Alive)
• http//www.cellsalive.com/mitosis.htm (Mitosis)