Cell Growth and Division

1. Cell Growth and Division Amy Yu Biology Honours Specialist AQ Mentor: Andrew Smereczynsky http://www.scientistsatwork.be/files/imagecache/foto_group/files/mitosis_cartoon_1.jpg

2. Genetics Vocabulary Energizer • “Quiz-Quiz-Swap!” • Find a partner, quiz each other, and then SWAP! • Uses • As a social, enjoyable activity to review unit vocabulary • To supplement Unit Test Review • Benefits • Engages variety of learners (visual, verbal, kinesthetic) • Opportunities for student peer feedback • Excellent formative assessment • Empowers students to familiarize with accurate terms

3. In the Curriculum …

4. Grade 10 Science Comparison

5. Grade 11 Biology Comparison

6. Student Challenges 1. Differentiating between mitosis and meiosis • Sex cells vs. somatic cells vs. body cells • What are gametes and when are they created? • haploid vs. diploid cells 2. Accurate vocabulary is required for accurate description of processes • “allele” and “gene” are used interchangably • “homologous pairs” often confused with “sister chromatids” or the ambiguous term “chromosomes” 3. Resources often do not depict a process, just a static picture of isolated stages /events

7. The classic textbook diagrams • Does not depict mitosis or meiosis as a dynamic, ongoing process • Observing dead mitotic cells under a microscope presents similar problems • Reinforces the misconception that cell division occurs in defined, isolated “stages” • Does not follow location of genes at different loci http://www.le.ac.uk/ge/genie/vgec/images/mitosis_meiosis.png

8. Studying “living” cells using microscope slides MISS!?!? I can’t see anything! http://www.biologycorner.com/resources/onionmitosis.jpg

9. Improving the Pencil-and-Paper Approach Bajema Strategy (Mertens & Walker, 1992) • Students use coloured pencils and draw 2 pairs of chromosomes • Genes (e.g. A/a or B/b) may be placed on them to trace their movement • (great alternative to the Mendelian punnett square algorithm) • Sequence of events in meiosis is traceable

10. Alternatives to paper approaches that emphasize the sequential nature of concept • Computer Animations The Stages of Mitosis http://www.youtube.com/watch?v=nPG6480RQo0&feature=related Meiosis http://www.youtube.com/watch?v=D1_-mQS_FZ0 • Computer Simulations Cell Division Gizmo www.explorelearning.com • Variety of manipulatives (pipe cleaners, magnetized chromosomes, etc.)

11. So What? • Poor conceptual organization can impede grasp of future, related concepts • Confusion about mitosis (Grade 10) can discourage students from learning meiosis in Grade 11 • Meiosis and genetic inheritance should be taught together to emphasize their relatedness

12. So What? • Isolated conceptual relationships are taught ambiguously and without connection to the overall picture • Where do homologous chromosomes come from?(one comes from maternal gamete, other from paternal gamete) • How are chromatid pairs formed? (DNA replication – Grade 12 concept) • How are chromsomal reduction, allelic segregation, and gene assortment related? (these are often depicted separately with separate diagrams, leading students to believe these are isolated events)

13. Consolidating the process: “Chromosomal Socks” Activity 4 stations = 4 “Tasks” 1 sock = 1 chromosome black clips = centromeres • As you move through the 4 different “Tasks,” consider: • grade/ level where “Task” could be used • where student misconceptions could present themselves • possible extensions • how each “Task” differs from another

14. Consolidating the process: “Chromosomal Socks” Activity • Addresses 3 key events of cell division with which students often have errors: chromosome doubling, pairing, and separating • Clarifies confusion between ploidy (# of sets of chromosomes) with chromosome structure, emphasizes the precision of the meiotic process • A kinesthetic, verbal activity which can help both students and teachers identify early misconceptions before they survive and are reinforced

15. Consolidating the process: “Chromosomal Socks” Activity Chinnici, Neth, and Somalin. “Using ‘Chromsomal Socks’ To Demonstrate Ploidy In Mitosis and Meiosis.” The American Biology Teacher (2006). 68(2):107.

16. Differentiating between Mitosis & Meiosis: Tools Individual or group activities that ask students to compare and contrast , differentiate,or make associations are excellent ways to catch early misconceptions and build each student’s confidence with genetics • Venn diagrams, T-charts • Scrambled terms: place on “mitosis” wall or “meiosis” wall • Students are given a term/ event and organize themselves into “Team Mitosis”, “Team Meiosis,” or both

17. the importance of words … Teacher: “Notice how during Metaphase I [in meiosis], the homologous pairs match up at the equator. This differs from metaphase in mitosis, where the sister chromatids line up at the equator.” Student: (confused) “Aren’t homologous chromosomes and sister chromatids the same thing?” [After backtracking for the 3rd time this week, this lesson goes over time and/or is unfinished, much to the teacher’s delight]

18. Mastering the Vocabulary: Tools • Foldables • ABC’s Activity: Vocabulary Brainstorm • Quiz-Quiz-Swap • Word Walls • Picture Cards

19. Role-Playing Mitosis • Materials • jerseys/ T-shirts of different colours (4 each) • stockcards with terms or concepts to be covered • Benefits • low-cost materials • engages all of the senses – appeals to auditory, kinesthetic, interpersonal and visual learners • concrete learning of an abstract concept • Extensions or Applications • can be extended to demonstrate meiosis, mistakes in meiosis leading to polyploidy

20. Applications and Societal Implications • Causes of cancer, cancer treatments • Stem cell research • Cloning • Genetic diseases arising from mistakes in meiosis (polyploidy), sex-linked diseases • Fertility and other reproductive issues

21. Formative Assessment IdeasLesson Sequence available in Handout • graphic organizers, collaborative learning activities, microscope labs Listen/watch for misconceptions, catch them early! • Bajema strategy pencil-and-paper check • Role Play Summary to ensure connection between physical activity and mental images of mitosis

22. Summative Assessment IdeasLesson Sequence available in Handout Possible Criteria to Evaluate Student Understanding of Cell Division • vocabulary • drawing or interpretation of phases • accurate labeling of structures • accurate depiction of sequential events Give students choice, differentiate possible products: • “Mitosis Booklet” or “Meiosis Booklet” • Comic strip – using Comic Life Technology • TV Script – TV skit • Animations • Poem or Song

23. Questions? Hopefully this can be added to your teacher toolbox! Thank You!