From Sex Cells to traits.

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From Sex Cells to traits.

• An introduction to meiosis and genetics

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Meiosis

• Meiosis is another kind of cell division. It is
  sex cell division.
• Meiosis creates gametes.

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Gametes

• Male gamete Sperm
• Millions produced at one time
• very small
• have a flagella to swim
• Produced in Testes

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Gametes

• Female gamete Egg
• one produced (3 polar bodies dissolve)
• large
• free moving
• Produced in Ovaries

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Meiosis

• Meiosis is the process
• for the formation of Gametes
• Meiosis is similar to mitosis
• but there is a second
• complete division.

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Meiosis

• Meiosis is done in a PMAT 1 and then goes through
  PMAT 2 to create a haploid number of chromosomes.

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Crossing over occurs during Prophase I
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Metaphase I

• Chromosomes line up
• NOTE - matching pairs line side by side
• (in mitosis, each chromosome is separate

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Anaphase I

• Chromosome PAIRS separate
• (In mitosis each half chromatid separates.

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Telophase I

• 2 cells separate

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Meiosis II

• NOW, the big difference is the process keeps
  going into PMAT 2.
• This is done to create the haploid number of
  chromosome. (half)

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Prophase II

• Each of the 2 cells prepares to divide again

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Metaphase II

• Chromosomes line up along middle.

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Anaphase II

• Sister chromatids separate.

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Telophase II

• Four haploid daughter cells are produced
• Each daughter cell has half the number of
  chromosomes from the parent cell

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Genetics

• Genetics is the study of heredity, a study of how
  certain characteristics are passed on from
  parents to children.

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Genes- Alleles

• A pair of hereditary factors that make up a gene
  (different forms of a gene)- Alleles

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Dominant

• A hereditary factor that takes over the gene
  determining the trait.
• Represented by a capital letter. Ex. BB or Bb.

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Recessive

• A hereditary factor that is hidden by a dominant
  allele.
• It is represented by a lower case letter.
• Ex. Bb or bb.

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