Cell Division

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• Cell Division
• Mrs. Morgan
• Biology
• Chapter 10

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Cell Division

• Cell division is the process where a cell divides
  into 2 daughter cells and each daughter cell has
  an identical set of chromosomes.

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Chromosomes

• Chromosomes are the structures within the cell
  that contain the genetic information that is
  passed on from one generation of cells to the
  next.
• The genetic information is in the form of DNA
  (DeoxyriboNucleic Acid).
• Chromosomes are made up of chromatin. During the
  early stages of mitosis, chromatin condenses and
  the chromosomes become visible.
• Chromatin is made up of DNA and protein.

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Source http//www.damours.iric.ca/Site/Projects.
html
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Source www.tetrasomy18p.ca
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The chromosome contains two sister chromatids
(identical parts) which are attached at the
centromere.
Source library.thinkquest.org. Image by
Chemobyl Frog Dissection
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The Cell Cycle
During the cell cycle, a cell grows, prepares for
division, and divides to form 2 daughter cells,
then both those cells begin the cycle anew.
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Interphase

• Interphase is the time between cell divisions and
  it can take a very long time when compared with
  the actual process of cell division.
• Interphase is divided into 3 phases, G1, S, and
  G2.
• G1 is the period of activity in which cellular
  growth and development takes place.
• Then S phase occurs. S phase is when DNA
  replication takes place.
• Finally, G2 phase involves the synthesis (making)
  of organelles and material necessary for cell
  division.
• Even though it seems as though the cell is
  inactive during Interphase it is actually
  involved in intense activity. Proteins are made,
  DNA is copied, ATP is made and used.

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Mitosis

• Mitosis is divided into 4 phases prophase,
  metaphase, anaphase, and telophase.

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Prophase

• Is the longest phase
• Chromosomes become visible because the chromatin
  has condensed and coiled up.
• Centrioles separate and move to opposite sides of
  the nucleus.
• The condensed chromosomes become attached to
  fibers at the centromere of each chromatid.
• Nucleolus disappears and the nuclear envelope
  breaks down.

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Metaphase

• Shortest phase of mitosis.
• The chromosomes line up across the center
  (equator) of the cell.
• Microtubules connect the centromere of each
  chromosome to the poles of the spindle. Because
  of their starlike arrangement around the poles of
  the spindle, these microtubules are called
  asters, which is Greek for star.Source
  Biology, Miller Levine, 4th ed.

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Anaphase

• The third phase.
• Begins when the centromeres that join the sister
  chromatids split. This causes the sister
  chromatids to separate, becoming individual
  chromosomes.
• The spindle grows longer.
• The chromosomes continue to move until they have
  separated into two groups near the poles of the
  spindle.

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Telophase

• The final phase of mitosis.
• The chromosomes begin to uncoil into a tangle of
  chromatin.
• The nuclear envelope reforms around the
  chromatin, the spindle begins to break apart, and
  a nucleolus becomes visible in each daughter
  cell.
• This is the end of mitosis, but not the end of
  cell division.

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Cytokinesis

• The result of mitosis is that there are two
  nuclei, each with a duplicate set of chromosomes.
• Cytokinesis, the division of the cytoplasm into
  two individual cells, quickly follows mitosis.

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http//www.cellsalive.com/mitosis.htm
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Whitefish Cell
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Onion root tip
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Source faculty.clintoncc.suny.edu