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9 Cards in this Set
- Front
- Back
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Does Nondisjunction occur in Meiosis or Meiosis II?
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Can occur in either:
Meiosis I homologous chromosomes fail to separate Meiosis II sister chromatids fail to separate. |
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A failure of chromosomes separating during meiosis is termed:
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Nondisjunction
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If two homologous chromosomes fail to separate during Meiosis I, how many copies will the 2 resulting gametes have?
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One gamete will have 4 copies and one will have none.
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After Meiosis II, the resulting gametes that originally underwent nondisjunction will result in:
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One will have 2 copies and one will have none.. it can fuse with another normal gamete and produce a zygote with 3 copies (trisomy) or one copy (monosomy).
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A zygote produced by one normal gamete and one that underwent Nondisjunction can result in:
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3 copies: trisomy
1 copy: monosomy |
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Syndrome: Individuals with only an X chromosome and no Y
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Turner's Syndrome
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Syndrome: External female appearance but underdeveloped ovaries and sterility.
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Turner's Syndrome
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Individuals will have male appearance if they have at least one Y, no matter how many X chromosomes are present. Individuals will have female genitalia if they have only X chromosomes: This arises from which genetic defect?
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Nondisjunction
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Down's Syndrome
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Trisomy 21
Mental retardation Abnormal growth |
