Cell Division

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Cell Division

• Section 8.2

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Cell Division

• Is the processis of a cell called a mother cell
  dividing into two daughter cells
• Reasons for Cell Division
• Cell too big
• Growth
• Repair replacement of damaged parts
• Reproduction of the species

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Types of Cell Division

• Binary Fission is the form of cell division used
  by prokaryotic cells.
• Mitosis is the most common form of eukarytoic
  cell division. A cell will replicate its entire
  DNA and divide into two daughter cells.
• Meiosis is the division of a diploid cell into
  (four) haploid ones. This cell division is found
  in multicellular organisms to produce haploid
  gametes

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Cell Division In Prokaryotes

• Binary Fission
• Prokaryotes have cell walls but lack nuclei or
  organelles

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Cell Division In Eukaryotes

• CELL CYCLE--Repeating set of events in the life
  of a cell
• Interphase
• A. G1
• B. S
• C. G2
• Cell Division
• A. Mitosis
• B. Cytokinesis

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FIVE MAJOR STAGES OF CELL CYCLE

• G1
• S
• G2
• MITOSIS
• CYTOKINESIS

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The Cell Cycle
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INTERPHASE

• Cell spends most of its time in this phase
• Grows, does cell stuff
• DNA is copied
• Prepares for cell division
• Cannot see chromosomes

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Interphase Cells
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MITOSIS

• Four Phases
• Prophase
• Metaphase
• Anaphase
• Telophase

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PROPHASE

• Chromosomes appear
• Nuclear envelope nucleolus disappear
• Centrioles move toward poles
• Spindles form

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Prophase Cells
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METAPHASE

• Replicated chromosomes (sister chromatids) line
  up across the equatorial plate
• Shortest phase

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Metaphase Cells
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ANAPHASE

• Sister chromatids split apart at centromere
• Each chromatid is now a separate chromosome
• Chromosomes moves toward poles

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Anaphase Cells
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TELOPHASE

• Chromosomes begin to untangle and form chromatin
• Nuclear envelope reforms, nucleolus reappears
• Spindles break apart
• Cell begins to squeeze in the middle

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Telophase Cells
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CYTOKINESIS

• Complete division of the cytoplasm forming two
  new cells
• Differs in plant and animal cells
• Animal Cells
• Cell membrane moves inward until the cytoplasm is
  pinched into two nearly equal parts
• Plant Cells
• Cell plate forms midway between the two new nuclei

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Cytokinesis
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Cytokinesis Cells
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