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15 Cards in this Set
- Front
- Back
Meiosis
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-Cell division that produces gametes
-These cells contain only half the number of chromosomes -These cells are said to contain a haploid (n) number of chromosomes -Meiosis occurs in two divisions |
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Difference between Mitosis and Meiosis
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Mitosis:
-1 division -diploid number (2n) -2 daughter cells -somatic cells -development/growth/repair -homologs do not associate Meiosis: -2 divisions -haploid number (n) -4 daughter cells -gametes -reproduction -homologs associate (tetrads) |
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Principle of Segregation
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each chromatid of a tetrad will end up in a different gamete
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Principle of Independent Assortment
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Alignment of chromosomes along the metaphase plate is indepedent of each other
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Crossing over
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exchange of alleles between non-sister chromatids of homologous chromosomes
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nondisjunction
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-homologous chrosomes fail to seprate in anaphase 1 or sister chromatids fail to seprare in anaphase 2
-result: one gamete with an extra chromosome/one gamete missing a chromosome |
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aneuploidy
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offspring with an extra or missing chromosome
-trisomic: extra -monosomic: missing one examples: trisomy 21, turner syndrom(xo), metfafemale(xxx), klinefelter syndrome(xxy)(xyy) |
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trisomy 21
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21st pair has three chromosomes
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polyploidy
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2 or more complete sets of chromosomes
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point mutation
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nucleotide of a gene
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deletion
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gene is delete
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duplication
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a delete fragment attaches to a chromatid of a homologous chromosome
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inversion
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deleted gene reattaches itself in reverse orientation
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translocation
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deleted fragment attaches to a nonhomologous chromosome
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cri du chat deletion
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fragments of 5 breaks off
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