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Bellwork 2-4-2014

Bellwork 2-4-2014. Look at the two different populations of organisms below: Which one is asexual and which one is sexual? Which one has variety and which once does not?. A. B. Missed work!!.

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Bellwork 2-4-2014

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  1. Bellwork 2-4-2014 • Look at the two different populations of organisms below: • Which one is asexual and which one is sexual? • Which one has variety and which once does not? A B

  2. Missed work!! • If you finish an assignment that was incomplete when I put in homework grades, turn it into the basket! • All in class work can be completed for full credit! Find a friend in the class if you are missing a lot of work! • Check grades

  3. Vocab Review • Chromosome – two chromatids put together, one complete set of information • Sister chromatids – make up a chromosome, half of the information • Homologous chromosomes – multiple pairs of chromosomes (two chromatids each), some from mom and some from dad

  4. Exploring Meiosis I • You will be exploring meiosis I on your own with your NEW lab group today • Following the guidelines at each lab bench, model EACH step of meiosis with the colored beads and chalk • After each step, YOU MUST GET CHECKED and then draw the step on your worksheet with colored pencils

  5. Your models Chromatid Chromosome Replication  **You will have 4 of these in total, all different colors!

  6. Check your drawings!

  7. Once you are done… • Separate sheet of paper • Homework if not done in class… • Describe the steps of meiosis using COMPLETE SENTENCES

  8. Bellwork 2-5-2014 • At which stage in meiosis I does the exchange of information occur? • How many cells does meiosis I create? • Are the products of meiosis I identical or is there variety?

  9. Meiosis

  10. Meiosis: Unit Vocabulary

  11. Meiosis Video • http://www.youtube.com/watch?v=wrxY4hjMDfk

  12. How much information? Whole set of DNA = 2n  Diploid Half set = n  haploid How to remember: Half – Haploid Di = 2

  13. How much information? n – haploid! 2n – diploid! Talk with your neighbor: Are chromatids haploid or diploid? Are chromosomes (pair of sister chromosomes) haploid or diploid?

  14. Interphase DNA replication Draw and label the centrioles on your Drawing How much information? 2n!! Diploid

  15. Prophase I Tetrads form and crossing over occurs Label the tetrads in your picture & where crossing over happens

  16. Prophase I Now we have double the amount of information in the cell… n or 2n?? 2n - Diploid!!!

  17. Tetrads & Crossing Over Crossing Over: Homologous chromosomes exchange small pieces, resulting in new chromosomes! Tetrads – close association of sister chromatids on homologous chromosomes

  18. Metaphase I Homologous chromosomes line up at the metaphase plate How much info? 2n – Diploid!

  19. Anaphase I Homologous chromosomes move to opposite ends of the cell Independent assortment occurs creating new combinations! How much info? 2n – Diploid!

  20. Independent Assortment Chromosomes from mom & dad RANDOMLY move to one side or the other

  21. Telophase I Cell walls begin to pinch inwards How much info? 2n – Diploid!

  22. (Cytokinesis I) Two daughter cells pinch off Talk to your neighbor… How do they compare to one another? n (haploid) or 2n (diploid?

  23. Why does genetic recombination matter? • Your turn!!! You will get two homologous chromosomes with your partner that look like this… Yellow: White: Red: Green: What traits do each potential individuals have?

  24. Why does genetic recombination matter? • Cross over at the indicated positions below Yellow: White: Red: Green: Now what traits do each potential individuals have?

  25. Why does genetic recombination matter? • Cross over at the indicated positions below Yellow: White: Red: Green: Now what traits do each potential individuals have?

  26. Prophase II Beginning with the end products of meiosis II Chromosomes are condensed and prepare for another division No crossing over!! n or 2n?

  27. Metaphase II Chromosomes line up at the metaphase plate More similar to mitosis this time Not homologous pairs any longer n or 2n?

  28. Anaphase II Chromatids move to either end of the cell n or 2n?

  29. Telophase II Chromatids separate to individual cells n or 2n?

  30. (Cytokinesis) Individual cells form n or 2n? Talk with your neighbor: How do the cells compare to each other? How do they compare to the products of meiosis I?

  31. What do we call these cells? These cells are called gametes  label Eggs in females Sperm in males n or 2n? They are haploid!!! Get half of information from mom, half from dad

  32. Fertilization – Making babies! Sperm + Egg = Zygote

  33. Mitosis vs. Meiosis # of divisions: # of divisions: Products: Products: Variety? Variety?

  34. Meiosis Card Sort Order the 11 cards to show the progress from a single cell in interphase and progressing to 4 haploid sex cells

  35. Funny Meiosis Video • http://www.youtube.com/watch?v=iCL6d0OwKt8

  36. Slate Quiz! • Look at the pictures on the following slides & name the stage of meiosis!

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