Meiosis

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Meiosis
A. Terms you should know 1. Homologous
Chromosomes 2. Locus 3. Autosomes 4. Sex
chromosomes 5. Diploid Cells 6. Haploid
Cells 7. Fertilization 8. Zygote 9.
Meiosis
10. Karyotype 11. Life Cycle 12. Asexual
reproduction 13. Sexual reproduction 14.
Clone
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B. Steps of Meiosis
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C. Mitosis vs. Meiosis
Event Mitosis Meiosis DNA Replication Occurs
during Occurs once, during the
interphase interphase before meiosis I of
Divisions One Two Synapsis Does not
occur Occurs during prophase I of daughter
cells Two Four Genetic composition Diploid,
genetically Haploid, genetically
of daughter cells identical nonidentical Role in
animal Create adult from Produces gametes
body zygote, Growth, Tissue repair
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D. How do we account for genetic variation?
1. Independent Assortment of
Chromosomes a. Metaphase I, how they are
situated on the metaphase plate b. Possible
combinations is 2n where n haploid number
So for humans it would be about 8 million
combinations 2. Crossing Over a. produces
individual chromosomes that combine genes
inherited from our two parents b. Occurs in
Prophase I c. homologous portions of two
nonsister chromatids trade places.
3. Random Fertilization 4. Mutations
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Crossing Over