Cell Reproduction and Heredity

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Cell Reproduction and Heredity
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• How do little elephants grow up to be BIG
  elephants?

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Why do animals shed their skin?
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Three reasons why cells reproduce by asexual
reproduction

• Growth
• 2. Repair
• 3. Replacement

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Animated Mitosis Cycle
http//www.cellsalive.com/mitosis.htm

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase Cytokinesis
• http//prezi.com/6dcz8acgjysx/mitosis/

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Animal Mitosis -- Review
Interphase                                                              Prophase                                                             
Metaphase                                                              Anaphase                                                             
Telophase                                                              Interphase                                                             
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Plant Mitosis -- Review
Interphase                                                              Prophase                                                             
Metaphase                                                              Anaphase                                                             
Telophase                                                              Interphase                                                             
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Plant vs. Animal

• PLANT
• Rigid cell walls do not pinch apart
• Cell plate forms between 2 new nuclei
• No centrioles

• ANIMAL
• Cell membrane pinches apart
• Has centrioles

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Asexual Reproduction

• Organisms produced from one parent like mitosis
• FISSION division of organism into parts
  (bacteria)

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Asexual Reproduction

• REGENERATION whole organism may develop from
  piece of organism or when organism is injured
  (sponges, planaria, sea stars)

• BUDDING organism grows from body of parent
  (hydra)

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Meiosis
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• Sexual Reproduction new organism produced when
  sex cells from 2 parents combine
• Sperm and Egg cell (104)
• Meiosis process of nuclear division that
  produces sex cells in the reproductive organs

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Meiosis

• Human cells have 23 pairs of chromosomes
• 46 total
• Sex cells have 23 chromosomes
• Why??
• Diploid cell that has 2 of every kind of
  chromosome
• Haploid Sex cell with 1 chromosome from each
  pair

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Meiosis
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46
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• Fertilization joining of egg and sperm
• Zygote cell that forms during fertilization
• The zygote will then undergo mitosis to develop

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Meiosis l ll

• Please look at your handout
• What do you see happening?
• Begins with 1 cell
• Meiosis l forms 2 cells
• Meiosis ll results in 4 cells

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Differences

• Mitosis
• 1 nuclear division
• Chromosomes line up singly
• Same of chromosomes
• 2 cells
• No crossing over

• Meiosis
• 2 nuclear divisions
• Chromosomes line up in pairs
• ½ number of chromosomes
• 4 cells
• Crossing over during Prophase I