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27 Cards in this Set
- Front
- Back
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Crossing over during meiosis can generate new combinations of maternal and paternal alleles on each homologous chromosome that results in ____
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Genetic Variation
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All possible maternal and paternal chromosomes have a(n) ____ probability of entering any gamete during meiosis
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Equal
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Abnormal meiosis results _____.
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Genetic Disorders
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Two cell division events enable one diploid to produce ___ haploid(s) that can develop into gametes, aka sex cells.
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four
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Meiosis enables the production of genetically variable ____.
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Gametes (Sex Cells)
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Where does meiosis occur in men?
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Testes
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Where does Meiosis occur in women?
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Ovaries
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Why are sexually-reproducing species dependent on meiosis?
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Maintain a constant number of chromosomes to ongoing generations
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When do homologous chromosomes separate during meiosis?
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Meiosis 1; anaphase 1
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When do sister chromatids seperate during meiosis?
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Meiosis 2; anaphase 2
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How are new allele combinations generated on each homologous chromosome?
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Crossing over, independent assortment
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Same gene, but different allele = ______
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Homologous chromosome
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When does crossing over occur?
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Prophase 1
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During crossing over, the maternal and paternal sister chromatids exchange ________.
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alleles
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Each cell contains EITHER the 2 maternal or the 2 paternal sister chromatids for chromosomes 1-22 and:
_____ in females _____ or _____ in males |
XX - females
XX or YY - males |
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_____ are attachment points formed between the non-sister chromatids during crossing over
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Chiasmata
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Crossing over during the prophase 1 binds the ____ together until the cell is ready to separate them during anaphase 1. This physical interaction is called _____.
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Homologous Chromosomes
Synapsis |
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What are the three major events of Meiosis 1?
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-Crossing Over
-Homologous pairs seperate -2 cells are formed |
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____ generates recombinant, homologous chromosomes with new combinations of maternal and paternal alleles.
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Crossing over
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Nonsister chromatids are held together during ____.
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Synapsis
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What is the result of crossing over?
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Recombinant chromosomes
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All possible combinations of maternal and paternal chromosomes can enter into ____ during meiosis
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Gametes
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Around 8 ____ possible chromosome combinations are possible in each gamete
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million
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Non-disjunction in anaphase 1 or 2 leads to ____.
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Aneuploidy
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Aneuploidy can result from an unusual number of ____ (non-sex chromosomes) in the fertalized egg (zygote)
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autosomes
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Why do some fertilized eggs with trisomy 21 survive compared to fertilized eggs with trisomy 1?
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Trisomy 1 would result in +3141 genes because of the many genes that it contains while trisomy 21 would result in a noticeably smaller amount of genes
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Chromosome #1 from mom and chromosome #1 from dad are called _____.
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Homologous chromosomes
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