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Quick review: identify this stage of the diploid cell cycle.

Quick review: identify this stage of the diploid cell cycle. Prophase. Quick review: identify this stage of the diploid cell cycle. telophase. Quick review: identify this stage of the diploid cell cycle. anaphase. Quick review: identify this stage of the diploid cell cycle. Prophase.

yolanda-russell
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Quick review: identify this stage of the diploid cell cycle.

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  1. Quick review: identify this stage of the diploid cell cycle. Prophase

  2. Quick review: identify this stage of the diploid cell cycle. telophase

  3. Quick review: identify this stage of the diploid cell cycle. anaphase

  4. Quick review: identify this stage of the diploid cell cycle. Prophase

  5. Quick review: identify this stage of the diploid cell cycle. metaphase

  6. Quick review: identify this stage of the diploid cell cycle. interphase

  7. Meiosis

  8. Meiosis • Defined: Process where the chromosome number is reduced by half • Gametes created (egg & sperm) • End Result: Four Haploid Cells

  9. Interphase • Same process • G1: Growth • S: Chromatin duplicated • G2: Growth

  10. Synthesis (S stage) Chromatin strands duplicated

  11. Prophase 1 Mom 1 • Similar as mitosis, except… • Two Events: • 1) Synapsis: Pairing of homologous chromosomes • Dad’s #1 chromosome pairs with Mom’s #1, etc… • The four paired chromatids equals a TETRAD • 2) Crossing Over: Exchange of genes Dad 1

  12. Early Prophase dad Chromosomes form dad dad mom Nucleus dissolves mom mom

  13. Synapsis tetrad tetrad dad Spindle fibers pull homologous chromosomes together dad dad mom mom mom tetrad

  14. Metaphase 1 • Homologous chromosomes (tetrads) align along cell equator dad mom mom dad mom dad

  15. Anaphase 1 • Homologous chromosomes are pulled apart to opposite ends • Tetrads separated mom dad mom dad dad mom

  16. Telophase 1 • Cytokinesis divides the cells • Each cell contains 1 of the homologous chromosomes mom dad mom dad dad mom

  17. Prophase 2 • Same as mitosis • Note: No new DNA was created (no 2nd interphase) mom dad mom dad dad mom

  18. Metaphase 2 • Remaining chromosomes are aligned at cell equator mom dad mom dad dad mom

  19. Anaphase 2 • Sister chromatids are pulled to opposite ends

  20. Telophase 2 • Cytokinesis divides the cells • Nucleus reforms on the four new cells • Chromatids uncoil • End Result: Four haploid cells

  21. spermatogonium Spermatogenesis Meiosis 1 • Defined: Production of sperm cells • Location: male testes • Makes final changes to sperm cell • Four haploid sperm cells at a time Meiosis 2 Spermatogenesis

  22. oocyte Oogenesis Meiosis 1 • Defined: Production of the egg cell (ovum) • In female ovaries • During meiosis I: Cytoplasm distributed unequally • After meiosis II: • 1 cell matures • 3 “Polar Bodies” dissolve Meiosis 2 Oogenesis

  23. Division of somatic cells Ex: Blood cells, skin cells, nerve cells… End Result: 2 Diploid Cells Importance: Replaces aging cells Importance: Form of asexual reproduction Division of gametes Ex: Sperm and Egg cells End Result: 4 Haploid cells Importance: Reduces the gamete chromosome number by half Mitosis Meiosis

  24. Kobe Kuiz 1) Name three ways that meiosis and mitosis differ. 2) Pick a stage of meiosis…any stage. Describe what happens in it. 3) What type of cells does meiosis create? 4) What are homologous chromosomes? 5) When do homologous chromosomes move to opposite ends of the cell? 6) When do chromatids move to opposite ends of the cell? 7) Why is no DNA created in meiosis 2? 8) How does meiosis differ in males vs. females?

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