Meiosis

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Meiosis

• Unit 4-3 Notes
• Mr. Hefti - Biology

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1. Definition

• Cell division that occurs only in gonads
  producing gametes.
• Spermatogenesis - in testes / results in sperm
  cells
• Oogenesis - in ovaries / results in egg cells
• Involves the same stages as mitosis!

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Meiosis I
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Meiosis II
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2. How many cells result?

• Complete process requires two cycles (meiosis I
  and II)
• 4 new cells are produced
• 4 viable sperm
• 1 / 4 egg cells viable

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3. What is the mathematical equation for meiosis?

• 2N ? 1N 1N 1N 1N
• A diploid cell divides and makes 4 new haploid
  cells

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4. How do the daughter cells compare to the
parent cell?

• Can be totally different!
• New combinations of chromosomes are possible due
  to crossing over
• Parent cells (in gonads) are diploid while
  gametes are haploid
• This is part of the reason sexual reproduction
  results in so much variation amongst offspring!!!

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