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Meiosis

Meiosis. Make a cover page: Your Name Chapter 11 Meiosis Feel free to decorate your cards as you go!. Diploid 2 sets of chromosomes in a cell. ½ from mom, ½ from dad. 2n All body cells are diploid. Made by MITOSIS. . Haploid 1 set of chromosomes in a cell. 1n

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Meiosis

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  1. Meiosis • Make a cover page: • Your Name • Chapter 11 • Meiosis • Feel free to decorate your cards as you go!

  2. Diploid 2 sets of chromosomes in a cell. ½ from mom, ½ from dad. 2n All body cells are diploid. Made by MITOSIS. Haploid 1 set of chromosomes in a cell. 1n All sex cells are haploid. Made by MEIOSIS. (2 separate flashcards)

  3. Not a flashcard. DIPLOID vs. HAPLOID 1n + 1n = 2n egg + sperm = new organism Haploid + Haploid = DIPLOID

  4. Gametes • Another name for sex cells: egg & sperm

  5. Zygote • A fertilized cell. • 2 gametes that are now together.

  6. Not a flashcard. In case you’ve never seen it for real…this is human DNA.

  7. Not a flashcard. This is a DIPLOID cell’s DNA. (2n) 23 Homologous pairs – one from mom and one from dad To do this, MITOSIS is used.

  8. Not a flashcard. This is a HAPLOID cell’s DNA. (1n) To do this, MEIOSIS is used.

  9. Meiosis • The making of gametes (eggs & sperm). • Cells contain ½ the normal amount of chromosomes. (haploid)

  10. Meiosis

  11. zygote egg WOW! That’s 2 full sets! sperm 26 52! + 26 = Why is meiosis necessary? • If the sex cells didn’t have ½ the amount of chromosomes, what would happen when the sperm & egg made a zygote? • Answer: Each baby would have twice the number of chromosomes as the parents!!!

  12. What is produced in meiosis? • 4 haploid cells (1n) • Each cell is genetically different! Cool!

  13. Not a flashcard. The cells produced during meiosis have DIFFERENT DNA!

  14. Not a flashcard. Review Meiosis Facts 4 • Makes ____ cells genetically different from parent cell & from each other • Makes _____ cells (1n or 2n?) • Makes ________________ • Used for ______________ 1n Gametes (sperm & eggs) sexual reproduction

  15. Spermatogenesis • Makes 4 sperm cells.

  16. Oogenesis • Makes 1 egg. (and 3 polar bodies)

  17. Not a flashcard. Spermatogenesis vs. Oogenesis

  18. Not a flashcard. What is different about meiosis? • Many different variations in the gametes. ___________________________________ • Divides twice, but only copies DNA once. ___________________________________ Makes cells with different genes than parent cell Makes cells with ½ the number of chromosomes as parent cell

  19. Phases of Meiosis I P M A TP M A T Meiosis 1 Meiosis 2 (I Peed on the MAT twice!) 

  20. Meiosis

  21. Meiosis I P M A T cytokinesis P M A T cytokinesis

  22. Mitosis vs MeiosisInterphase Interphase I • DNA spread out as chromatin • Nuclear membrane visible • DNA copied during S phase Same as mitosis!

  23. Mitosis vs Meiosis Prophase Prophase I • DNA scrunches into chromosomes • Nuclear membrane disappears • Centrioles appear Same, except… Homologous pairs match up XX XX XX X X X

  24. Crossing Over • Chromatid arms trade DNA with each other. • Produces daughter cells with different gene combinations.

  25. Mitosis vs Meiosis Metaphase Metaphase I • Chromosomes line up in middle Chromosomes line up in middle with homologous partner

  26. Mitosis vs Meiosis Anaphase Anaphase I • Chromatids split and move apart. • Chromatids stay together • Homologous pairs move apart

  27. Mitosis vs Meiosis Telophase Telophase I • Two nuclei • Nuclear membrane returns • DNA spreads out as chromatin Same as mitosis!

  28. Mitosis vs Meiosis Cytokinesis Cytokinesis I • Cytoplasm splits into 2 cells Same as mitosis!

  29. Mitosis vs Meiosis Prophase Prophase II • DNA scrunches into chromosomes • Nuclear membrane disappears • Centrioles appear Same as mitosis!

  30. Mitosis vs Meiosis Metaphase Metaphase II • Chromosomes line up in middle Same as mitosis!

  31. Mitosis vs Meiosis Anaphase Anaphase II • Chromatids split and move apart Same as mitosis!

  32. Mitosis vs Meiosis Telophase Telophase II • Two nuclei • Nuclear membrane returns • DNA spreads out as chromatin Same as mitosis!

  33. Mitosis vs Meiosis Cytokinesis Cytokinesis II • Cytoplasm splits Same as mitosis!

  34. Mitosis vs Meiosis In Meiosis: • (Prophase I) Homologous pairs match up. • (Prophase I) Crossing over creates • genetic differences. • Cells divide twice but only copies DNA • once- this makes haploid cells.

  35. Meiosis

  36. The end. Really. • Test date: • How to succeed on GHS biology tests: • Memorize the flashcards. • Practice with friends, by yourself, or with family. • Read the book. • It is easy reading. • Reading the text helps you understand the written part. • Do all labs, homework, and worksheets. • If you missed any days, make sure you made up any work!

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