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Bell Ringer

Bell Ringer. Cell Division Review. Units 5 & 6. Prokaryotic Cell Division. Prokaryotic Cell Division = Binary Fission After DNA replication occurs, the cytoplasm divides. There is NO nucleus, so mitosis does NOT happen. DNA Replication. Cytokinesis.

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Bell Ringer

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  1. Bell Ringer

  2. Cell Division Review Units 5 & 6

  3. Prokaryotic Cell Division • Prokaryotic Cell Division = Binary Fission • After DNA replication occurs, the cytoplasm divides. There is NO nucleus, so mitosis does NOT happen.

  4. DNA Replication Cytokinesis This process is called Binary Fission

  5. This is the Cell Cycle M Phase

  6. Eukaryotic Somatic (Body) Cell Division = Mitosis Stages of Cell Cycle • Interphase • G1 = Growth • S = DNA replication • G2 = Prepare for Mitosis • M Phase • Mitosis = Division of Nucleus • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis = Division of Cytoplasm

  7. MITOSIS REPRODUCTION OF BODY CELLS PRODUCES 2 IDENTICAL DIPLOID CELLS

  8. Interphase • Cell Grows & Prepares for Division • DNA is Replicated

  9. Prophase • Chromosomesbecome visible • Nuclear Membrane & Nucleolus Disappear • SPINDLE FORMS EARLY LATE

  10. Metaphase • Spindle Fibers attach to the Centromeres • Chromosomes Line up in the Middle/ Equator

  11. Anaphase • Sister Chromatids are Pulled Apart (separated) to opposite poles of the cell

  12. Telophase • Nuclear Membrane & Nucleolus Reform • Chromosomes Unwind into Chromatin

  13. Cytokinesis • Cytoplasm Divides • 2 Identical daughter cells form with the SAMEnumber of chromosomes as parent cell Occurs during Telophase

  14. MITOSIS END RESULT: Produces 2 Genetically Identical Diploid Body (Somatic) Cells

  15. Cytokinesis • ANIMAL CELL • PLANT CELL

  16. MEIOSIS REPRODUCTION OF SEX CELLS PRODUCES 4 GENETICALLY DIFFERENT HAPLOID GAMETES

  17. Interphase • Cell Grows & Prepares for Division • DNA is Replicated

  18. Meiosis I Anaphase I Telophase I Prophase I Metaphase I

  19. 2 Stages of Division Meiosis II HAPLOID 4 Prophase II Metaphase II Anaphase II Telophase II

  20. Crossing Over Synapsis/Tetrad = Homologous Chromosomes Pair Up & Cross Over • Crossing Over begins during Prophase I& ends during Anaphase I • Crossing Over is important because • It increases Genetic Diversity • It ensures that all cells produced during meiosis are Different • It Unlinksgenes

  21. Homologous Chromosomes Pair Up & Cross Over Homologous Chromosomes Line Up In The Middle (double line)

  22. Meiosis I Homologous Chromosomes Separate

  23. Spindle Reforms & Chromosomes Attach Chromosomes Line Up in the Middle (single line) Sister Chromatids Separate

  24. Meiosis II Produces 4 Genetically Different Haploid Gametes (Sex Cells)

  25. 1ovum (egg) produced 4 sperm produced Fertilization Zygote

  26. Karyotype: Male or Female?

  27. Karyotype: Male or Female?

  28. Human Gametes normally have 23chromosomes. Human Body Cells normally have 46chromosomes (23pairs).

  29. What is this disorder called? Down’s SyndromeOR Trisomy 21 This is caused by Nondisjunction. Nondisjunction can occur during Anaphase IOR Anaphase II of meiosis if the chromosomes do not SEPARATEcorrectly.

  30. Stage of Meiosis = Anaphase II Stage of Meiosis = Anaphase I Too Many Chromosomes

  31. Crossing Over Homologous Chromosomes Line Up in the Middle/Equator Chromosomes Line Up in the Middle/Equator Homologous Chromosomes Separate Sister Chromatids Separate Diploid Haploid 4 2 Identical Body Cells Genetically Different Gametes (sex cells)

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