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Cell Division

Cell Division. SOL: BIO 6 a-c. Meiosis. Meiosis occurs in sexual reproduction when a diploid germ cell produces four haploid daughter cells that can mature to become gametes (sperm or egg). from mom. from dad. child. too much!. meiosis reduces genetic content. Meiosis.

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Cell Division

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  1. Cell Division SOL: BIO 6 a-c

  2. Meiosis • Meiosis occurs in sexual reproduction when a diploid germ cell produces four haploid daughter cells that can mature to become gametes (sperm or egg).

  3. from mom from dad child too much! meiosis reduces genetic content Meiosis Goal: reduce genetic material by half Why? n (mom) + n (dad) = 2n (offspring) Just right!

  4. Meiosis I (reduction division) Meiosis II Diploid Haploid Haploid Meiosis: cell division in two parts Sister chromatids separate Chromatids separate (equational division) 2n n n Result: one copy of each chromosome in a gamete.

  5. Spindle fibers Nucleus Nuclear envelope Prophase I (early) (diploid) Prophase I (late) (diploid) Metaphase I (diploid) Anaphase I (diploid) Telophase I (diploid) Meiosis I : the reduction division

  6. Prophase I Early prophase Chromatids pair. Crossing over occurs. Late prophase Chromosomes condense. Spindle forms. Nuclear envelope fragments.

  7. Metaphase I Chromatid pairs align along the equator of the cell.

  8. Anaphase I Chromosomes separate and move to opposite poles. Sister chromatids remain Attached at their centromeres.

  9. Telophase I Nuclear envelopes reassemble. Spindle disappears. Cytokinesis divides cell into two.

  10. Sister chromatids carry identical genetic information. Meiosis II produces gametes with one copy of each chromosome and thus one copy of each gene. Meiosis II Gene X

  11. Four Non-identical haploid daughter cells Prophase II (haploid) Metaphase II (haploid) Anaphase II (haploid) Telophase II (haploid) Meiosis II : the equational division

  12. Prophase II Nuclear envelope fragments. Spindle forms.

  13. Metaphase II Chromosomes align along equator of cell.

  14. Anaphase II Sister chromatids separate and move to opposite poles.

  15. Telophase II Nuclear envelope assembles. Chromosomes unravel. Spindle disappears. Cytokinesis divides cell into two.

  16. Results of meiosis • Four haploid cells • One copy of each chromosome

  17. “Putting It All Together” - Fertilization

  18. What Meiosis is About Meiosis allows the creation of unique individuals through sexual reproduction.

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