Cell Division

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Cell Division

• In eukaryotic cellsDNA is contained in the
  nucleus. The nucleus contains material called
  CHROMATIN. Chromatin is made of DNA and protein.
  Most of the time.chromatin appears as dark
  patches within the nucleus.
• At the start of mitosis, the chromatin begins to
  coil up condensing into thick short rods that
  become visible under the microscope. The
  chromatin is now called CHROMOSOMES.

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CHROMATIN

• Made of DNA and protein

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CHROMOSOME

• Made of DNA and protein
• may be single stranded or double stranded

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CHROMATID

• Single arm of chromosome

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Duplicated chromosome

• Has 2 chromatid arms
• Each chromatid arm is a duplicate of its partner
  (genetic duplicate)

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Centromere

• Point at which 2 chromatids are joined

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Cell division in Eukaryotic cells ( 2 processes)

• 1. Mitosis process by which the NUCLEUS of a
  eukaryotic cell divides into 2 NUCLEI. Each
  containing a complete set of chromosomes.
• 2. Cytokinesis cellular division (cytoplasm and
  organelles)

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INTERPHASE

• Time between mitosises NOT a phase of mitosis.
  (most time spent in interphase)
• 1. Duplicate genetic material
• 2. Produces necessary of organelles
• 3. Chromosomes are not visible. Genetic material
  appears as chromatin

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The steps of mitosis.

• Prophase
• Metaphase
• Anaphase
• Telophase

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PROPHASE

• Mitosis begins1st phase
• 1. Chromosomes coil up become visible
• 2. Nuclear envelope breaks down
• 3. Spindle fibers form

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METAPHASE

• 1. Chromosomes are attached to the spindle fibers
  (at centromeres)
• 2. Chromosomes are lined up on the equator
  (midline)
• Meta middle

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ANAPHASE

• 1. Spindle fibers shorten.pulling the
  chromosomes apart at the centromere (spindle
  fibers start to break down)
• 2. Each chromatid moves to opposite poles (each
  chromatid is now called a chromosome)

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TELOPHASE

• 1. Each side (pole) of the cell has a complete
  set of chromosomes
• 2. Nuclear envelopes begin to reform around each
  set of chromosomes
• 3. Chromosomes begin to uncoil

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CYTOKINESIS

• 1. Each cell now has a complete set of
  chromosomeschromosomes are now chromatin
• 2. Nuclear envelopes completely formed
• 3. Cytoplasm organelles divide