Write everything that is underlined

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Section 6-2Meiosis

• Write everything that is underlined

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KEY CONCEPT During meiosis, diploid cells
undergo two cell divisions that result in haploid
cells
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A. Cells go through two rounds of division in
meiosis

1. Meiosis reduces chromosome number and creates
   genetic diversity

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1. Meiosis I and meiosis II each have four phases,
   similar to those in mitosis

• Pairs of homologous chromosomes separate in
  meiosis I
• Homologous chromosomes are similar but not
  identical
• Sister chromatids divide in meiosis II
• Sister chromatids are copies of the same
  chromosome

homologous chromosomes
sister chromatids
sister chromatids
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• Meiosis I occurs after DNA has been replicated
• Meiosis I divides homologous chromosomes in four
  phases

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• Meiosis II divides sister chromatids in four
  phases
• DNA is not replicated between meiosis I
  andmeiosis II

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Listen Up!

• http//www.youtube.com/watch?vnM-L6q8u_58safety_
  modetruepersist_safety_mode1
• Follow along on a sheet Miss Walsh will pass out.
  
• Goofy? Yes. Helpful? Absolutely!!!!!

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Hands On!

• Each table will receive 5 pieces of yarn- one big
  piece, tied into a circle, and 4 little pieces,
  which represent homologous chromosomes.
• Miss Walsh will call out a step of meiosis I-
  using your textbook (page 174) and pieces of
  yarn, demonstrate each step.
• Miss Walsh will call out the phases of meiosis
  II- use your textbook (page 175) and yarn to
  demonstrate each step. (You are going to need
  scissors for Meiosis II)

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1. Meiosis differs from mitosis in significant ways

• Meiosis has two cell divisions mitosis has one
• In mitosis, homologous chromosomes never pair up
• Meiosis results in haploid cells mitosis results
  in diploid cells

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B. Haploid cells develop into mature gametes

1. Gametogenesis is the production of gametes
2. Gametogenesis differs between females and males

• Sperm become streamlined and motile
• Sperm primarily contribute DNA to an embryo

• Eggs contribute DNA, cytoplasm, and organelles to
  an embryo
• During meiosis, the egg gets most of the
  contents the other cells form polar bodies

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The Fate of the 4 Haploid Cells

• If it is from the male parent, all 4 will become
  sperm cells
• If it is from the female parent, 1 will be an egg
  and the other 3 gametes die

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• Pick 1 of the 3 below
• -Draw and label the following picture
• Write a paragraph about what is happening in the
  pictures
• Write a rap about what is occurring in the
  pictures

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DNA copies itself
Diploid Parent Cell
1st meiotic division (haploid)
2nd meiotic division (haploid)