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Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Concept Presentation: Cell Division and Growth Background Information Cell Division and Growth is a concept that is prevalent in the Grade 10 Science Biology strands, as well as the Grade 11 Biology Genetics strands in the revised curriculum. Students are introduced to cells primarily in Grade 8, with earlier grades focusing on the related concepts of tissues, organs, and characteristics of living things. This concept presentation will focus on how to make the concept of Cell Division and Growth more dynamic and concrete for student learning. There are challenges for the average classroom to demonstrate the abstract process of mitosis and meiosis under a simple microscope. Therefore, varied hands-on experiences and interactive group work are introduced in this presentation in order to help students collaboratively grasp the intricate and complex processes of cell division. This presentation will focus on three strategies to help overcome the major student challenges: differentiation between mitosis and meiosis; accurate vocabulary and communication to describe these processes; and the understanding that cell division and growth is a process, not a series of static stages. Map of Concept through K-12 Curriculum Please see page Appendix A, or separate link on Wiki. Essential Expectations Grade 10 Applied Science- Tissues, Organs, and Systems (Biology Strand) B1.2 evaluate the effects that use of or exposure to a technology, substance, or environmental factor may have on the function of human tissues, organs, or systems B2.1 use appropriate terminology related to human cells, tissues, organs, and systems B2.2 examine cells under a microscope or similar instrument to identify the various stages of mitosis in animals B2.4 compare, on the basis of observation, the division of cancerous cells and non-cancerous cells, and describe the impact of cancerous cells on the human body B3.1 describe the cell cycle in animals, and explain its importance for the growth of cells and repair of tissues Grade 10 Academic Science – Tissues, Organs, and Systems of Living Things (Biology Strand) B1.1 analyse, on the basis of research, ethical issues related to a technological development in the field of systems biology, and communicate their findings B1.2 assess the importance to human health and/or society of medical imaging technologies used in Canada in diagnosing or treating abnormalities in tissues, organs, and/or systems B2.1 use appropriate terminology related to cells, tissues, organs, and systems of living things B2.2 examine cells under a microscope or similar instrument to identify the various stages of mitosis in plants and animals B2.5 investigate the rate of cell division in cancerous and non-cancerous cells, using pictures, videos, or images, and predict the impact of this rate of cell division on an organism Amy Yu Honours Specialist Biology AQ B3.1 Summer 2010 EAQ2020Y-Y-60 describe the cell cycle in plants and animals, and explain the importance of mitosis for the growth of cells and repair of tissues B3.2 explain the importance of cell division and cell specialization in generating new tissues and organs B3.3 explain the links between specialized cells, tissues, organs, and systems in plants and animals Grade 11 College Biology – Genetics (Strand D) D1.1 evaluate, on the basis of research, some of the social and ethical implications of genetic research and reproductive technologies D2.1 use appropriate terminology related to genetics D2.2 investigate the process of meiosis, using a microscope or computer simulation, and identify, and draw biological diagrams of, the phases of meiosis D3.1 explain the process of meiosis in terms of cell division and the movement of chromosomes D3.2 explain how the concepts of DNA, genes, chromosomes, alleles, mitosis, and meiosis account for the transmission of heredity characteristics from generation to generation D3.3 describe some genetic disorders that are caused by chromosomal abnormalities or other genetic mutations D3.4 describe reproductive technologies such as cloning, artificial insemination, and in vitro fertilization Grade 11 University Biology Strand D: Genetic Processes D1.1 analyse, on the basis of research, some of the social and ethical implications of research in genetics and genomics D1.2 evaluate, on the basis of research, the importance of some recent contributions to knowledge, techniques, and technologies related to genetic processes D2.1 use appropriate terminology related to genetic processes D2.2 investigate the process of meiosis, using a microscope or similar instrument, or a computer simulation, and draw biological diagrams to help explain the main phases in the process D3.1 explain the phases in the process of meiosis in terms of cell division, the movement of chromosomes, and crossing over of genetic material D3.2 explain the concepts of DNA, genes, chromosomes, alleles, mitosis, and meiosis, and how they account for transmission of hereditary characteristics according to Mendelian laws of inheritance D3.4 describe some genetic disorders caused by chromosomal abnormalities or other genetic mutations in terms of chromosomes affected, physical effects, and treatments D3.5 describe some reproductive technologies, and explain how their use can increase the genetic diversity of a species Strand C: Evolution C3.4 describe some evolutionary mechanisms (genetic variation, genetic drift, biotechnology), and explain how they affect the evolutionary development and extinction of various species Grade 12 University Biology: Strand D – Molecular Genetics D3.1 explain the current model of DNA replication, and describe the different repair mechanisms that can correct mistakes in DNA sequencing Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Description of Difficulties/ Misconceptions 1. Differentiating between mitosis and meiosis • Students often confuse the types of cells and the processes that they undergo (e.g. sex cells, body cells, somatic cells, gametes) • What are gametes and when/how are they created? • The concepts of chromosomes numbers and ploidy are especially challenging for students – differentiating between 1n, 2n, haploid, diploid, polyploidy 2. Accurate vocabulary is required for accurate description of processes • “allele” and “gene” are used interchangeably – problematic especially for future lessons on inheritance and Mendelian heredity • “homologous pairs” often confused with “sister chromatids” or the ambiguous term “chromosomes” – these terms are especially crucial to the accurate description of cell division processes 3. Resources often do not depict a process, just a static picture of isolated stages /events Textbook diagrams offer particular challenges for teachers, including that They do not depict mitosis or meiosis as a dynamic, ongoing process They often reinforce the student misconception that cell division occurs in defined, isolated “stages” They do not offer students the chance of follow certain genes at different loci • Observing dead mitotic cells under a microscope presents similar problems Microsope specimens are dead and may lead students to believe that each division stage is static and unchanging Advance Preparation/ Special Materials Needed 1. Quiz-Quiz-Swap Vocabulary Activity - on cue cards or similar materials, prepare or have students prepare cards - on one side, write out the term in CAPITAL letters - on the other side, write out the definition and/or appropriate picture for the term 2. “Chromosomal Socks” Activity - use a garbage bag or a similar bag to put the socks in (this represents the “nuclear membrane”) - obtain a variety of pairs of socks – ensure each has a matching pair - clothespins to represent centromeres - red or blue sock to represent X and Y chromosome - optional foam board and long pins to create “karyotypes” of chromosome socks Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 3. Role-Playing Mitosis - jerseys of different colours – each student pair should have 1 colour - can obtain these from physical education department, or have students bring them in - cards bearing the terms “homologous pair,” “sister chromatid,” “centromere,” or any other cell parts/ terms/ concepts you would like to cover 4. Active Folders, T-Charts, Venn Diagrams, Word Walls, Picture Cards - have a variety of cardstock, construction paper, scissors markers, and glue available - accommodations: for applied classes or students with needs, a list of premade terms and definitions (matched or unmatched) may be provided to the students to scaffold the activity 5. Gizmos at www.explorelearning.com - effective, online computer simulations of many scientific and mathematical concepts - book computer labs and/ or have a SMARTboard ready for classroom use - most boards will have a subscription for Gizmos, enquire with your Instructional Leader - you may pre-print the “Student Worksheet” and have students complete this as an assessment piece 6. Multimedia Animations - LCD projector, Internet connections - alternatively, download the videos and embed in powerpoint using specialized software 7. Other Manipulatives to model Chromosome Activity - pipe cleaners, play-doh, magnetized chromosomes Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Lesson Sequence and Assessment & Evaluation for Grade 10 (modify for Applied or Academic as you see fit) Description of Activity Day 1: 1.Cell Part Pass Activity 2. Why do Cells Divide? (mind map, brainstorm) 3. Quick Note: Cell Cycle 4. Vocabulary: Create an Active Folder or a Graphic Organizer (homework) Day 2: 1. Quiz-Quiz-Swap 2. Quick Note: The phases of Mitosis 3. Lab: Observing Onion Root Cells or Whitefish Mitotic Cells -using a microscope and correct microscope skills, identify and draw at least 2 different cells undergoing 2 different stages of mitosis (Homework) Day 3: 1. Hand in Lab 2. Role Playing Mitosis Activity: pose problems for students to solve (see Teaching Ideas) 3. Role Play Summary: students summarize visually and in writing teacher-introduced terms, phrases, and events encountered during Role Play (Homework) Day 4: 1. Collect Role Play Summaries 2. “Chromsomal Socks” Activity: Assign Task as you see fit (see Teaching Ideas), 3. Pencil-and-Paper Activity: Students work on Bajema worksheet and follow chromosomal movement during mitosis (Homework) Day 5: 1. Take up Bajema worksheet 2. Assignment: Create a “Mitosis Booklet” which covers vocabulary, drawings of phases, and labeling of structures or events during mitosis. Teaching/Learning Strategies Expectat -ions Learning Styles Assessment Cooperative Learning B2.1 (2P) B3.1 (2P) Auditory Visual Kinesthetic Diagnostic -collect Cell Pass activity to determine prior knowledge from Grade 8 - listen to brainstorming Auditory Visual Kinesthetic Formative - observe student interactions for vocabulary use Groupwork, Teacherled discussion Direct Instruction Independent work Cooperative Learning Direct Instruction Lab skills: communication performing, recording, interpreting Independent Work Cooperative Learning Problem-solving B2.1 (2D) B3.1 (2D) B3.2 (2D) B2.1 (2P) B2.2 (2P) B2.4 (2P) B3.1 (2P) Logical Analytical B2.1 (2D) B2.2 (2D) B3.1 (2D) B2.1(2P) B3.1 (2P) B2.1 (2D) B3.1 (2D) Visual Auditory Kinesthetic Interpersonal Logical Independent Work B2.1 (2P) B3.1 (2P) Cooperative Learning Problem-solving B2.1 (2D) B3.1 (2D) Group Discussion Independent Work B2.1 (2P) B3.1 (2P) B2.1 (2D) B3.1 (2D) Auditory Visual Kinesthetic Interpersonal Logical Visual (although booklet can be another DI product – i.e. comic strip, TV script, etc.) Formative - observe students perform lab, and see if link from Note/Lab was made Formative - mark lab for skills, product Formative -observe role-play - observe creation of Summary to ensure that physical activities is connected with mental images of mitosis Formative - look over Role Play Summaries for any misconceptions - listen, watch, question during Socks Activity - use Bajema sheet to catch any misconceptions Formative: Take up homework to identify level of understanding Summative: Evaluate student understanding of cell division (K, COM) Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Teaching Ideas 1. Quiz-Quiz-Swap Activity - each student receives a card with the term on one side, and the definition on the other - raise your hand – this indicates that you need a partner - once you have your partner, give them a high five! Show your partner the definition/picture side only – your partner will guess the correct term that it describes - if your partner is having difficulty, you may give him or her hints - 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 2. “Chromosomal Socks” Activity - this activity may be modified to be a demo or a full class activity - divide class into groups, each group receives the bag full of socks, as well as clothespins (the centromeres) - Note: The value in this activity is demonstrating the dynamic process of meiosis or mitosis; therefore, it is not advised to ask any group to just model one phase without showing transitions into other phases. A) Possible Tasks (vary according to student material, lesson sequence, grade, complexity, or necessary accomodations): - Model the phases of mitosis, from prophase to telophase - Model the phases of mitosis, and indicate when the following structures appear: homologous chromosomes, sister chromatids, centromeres, equatorial plate - Model the phases of meiosis, from prophase I to telophase II - Model the phases of meiosis, and identify the where the following events occur: random assortment, crossing over, transition from 2n ploidy to 1n, tetrad B) Possible higher-order thinking questions to include while students are completing the task Mitosis Questions - Where do homologous chromosomes come from? (maternal vs. paternal chromosome) - What events must occur for sister chromatids to formed? (DNA Replication) - What structure represents replicated DNA – homologous chromosomes or sister chromatids? (sister chromatids) - Where are centromeres found? (on sister chromatids, not between homologous chromosomes!) - When does cytokinesis occur? How does this differ between plants and animals? Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Meiosis Questions - Why is meiosis considered to be a “reductional” division, and mitosis is not? - Which stage of meiosis is most similar to metaphase in mitosis? Why? (metaphase II in meiosis is most similar to metaphase in mitosis – sister chromatids line up on equatorial plane) - Explain the components of, and the events undergone by, a “tetrad.” Why is the tetrad structure important for genetic variation in a species? - How can you relate this to monohybrid or dihybrid crosses? 3. Role-Playing Mitosis - begin with 2 pairs of students - each pair of students should be wearing one type/colour of jersey - other students form a circle around the 2 pairs of student Explain to students that: 1) The students with the coloured jerseys represent chromosomes containing genes 2) The students forming the circle represent the cell membrane 3) Together that students represent a mature parent cell that is “normal” Pose a problem for the students (the “key question”): “You, the parent cell, must produce another cell like yourself. It can be smaller in size, but must be able to control the same activities that you control.” - let students discuss, and try some regrouping (trial and error) - class will make 2 new circles (2 new cell membranes) - students will now notice that there are only ½ the number of chromosomes in each daughter cell, compared with the original daughter cell Scaffolding – Propose to the students that students with jerseys need to be doubled - students may suggest that doubling should happen in parent cell before the two new cell circles form, or after new cell circles form (opportunity for discussion about alternative hypothesis for cell reproduction) - other concepts that can be incorporated into the activity: cytokinesis (and how that differs from mitosis) - give different students opportunities to play chromosomes or cell membrane Applications and Societal Implications Cell division and growth is a concept that plays a major role in today’s biotechnological advances and medical research. Topics that could be related to this concept are: o causes of cancer and cancer treatments o stem cell research o cloning o genetic diseases: polyploidy, sex-linked diseases, etc. o fertility and other reproductive issues Amy Yu Honours Specialist Biology AQ Summer 2010 EAQ2020Y-Y-60 Annotated References 1. Ministry of Education. “Science.” The Ontario Curriculum Grades 1-8 (2007) Ministry of Education. “Science.” The Ontario Curriculum Grades 9 and 10 (2007) Ministry of Education. “Science.” The Ontario Curriculum Grades 11 and 12 (2007) The Ontario Ministry of Education outlines the curriculum in terms of big ideas, overall expectations, and specific expectations. 2. Brown, C.R. “Some misconceptions in meiosis shown by students responding to an Advanced level practical examination question in biology.” Journal of Biological Education (1990). 24(3): 182-185. Students often have difficulty with the concepts of duplication of chromosomes into chromatids, the meiotic separation of chromosomes, and the meaning of the term allele. The paper discusses how these misconceptions will almost inevitably lead to problems with future concepts, such as monohybrid and dihybrid crosses of Mendelian genetics. The researchers followed a large sample of students to determine the frequency of these misconceptions, as well as their performance during a practical biology Advanced level examination. They focused on how students answered one multi-part question in particular. They found that students had difficulty in the following areas: duplication of chromosomes into chromatids; sister chromatids carrying the same allele(s); and the terms “heterozygote” and “locus.” The writers interpreted the results as evidence that the current methods of teaching cell division rely too heavily on the “static description of named stages.” Other methods involving the dynamic, three-dimensional treatment of the process as well as simple model-building to pinpoint misconceptions was recommended. 3. Stavroulakis, Anthea M. “Meio-Socks & Other Genetic Yarns.” The American Biology Teacher (2005). 67(4): 233-238. This article presents a method of teaching cell division using socks and yarn, which is a visual and handson method for both students and instructors. This method is considered by the writers to be a more dynamic way of teaching and examining the meiotic process at the middle and high school, as well as college, levels. This method also allowed students more time to sort chromosome pairs and to figure out how to accurately complete the tasks involved. Consequences arising from errors during the meiotic process may also be discussed. The writer has found that using this method, students were more engaged and their understanding of meiotic concepts was enriched and improved. 4. Cho, Hee-Hyung, Kahle, Jane Butler, and Nordland, Floyd H. “An Investigation of High School Biology Textbooks as Sources of Misconceptions and Difficulties in Genetics and Some Suggestions for Teaching Genetics.” Science Education (1985). 69(5): 707-719. In the 1980’s, textbooks were the curriculum for most science courses; researchers investigated conceptual organization of textbooks to see if there were any sources of misconceptions for students. The identification of such sources would then allow teachers to design more appropriate instructional materials. The four major misconceptions found in the textbooks were: conceptual organization; conceptual relationships; and use of terms. Suggestions by researchers include the psychological sequence of instruction starting with genetics and meiosis, followed by chromosome theory, which may be extended to protein synthesis. More specific diagrammatic representations in student resources are also recommended. Amy Yu Honours Specialist Biology AQ 5. Summer 2010 EAQ2020Y-Y-60 Dreyfus, Amos, and Jungwirth, Ehud. “The pupil and the living cell: a taxonomy of dysfunctional ideas about an abstract idea.” Journal of Biological Education (1989). 23(1): 49-55. Researchers conducted a questionnaire and interviews with tenth grade pupils who had been taught about the living cell the previous year. It was found that many misconceptions survived because they were socially, but not scientifically, functional in the classroom situation; that is, the misconceptions had remained undetected by the teachers or were even regarded as acceptable analogies by teachers. The study stresses the need for an early diagnosis of such misconceptions is imperative to prevent their survival and even reinforcement. In order to avoid misconceptions, a teaching approach in which a concept is described by means of meaningful attributes, and linked to other, related concepts, should be used. 6. Mertens, Thomas R., and Walker, Julie O. “A Paper-&-Pencil Strategy for Teaching Mitosis & Meiosis, Diagnosing Learning problems & Predicting Examination Performance.” The American Biology Teacher (1992). 54(8): 470-474. The Bajema strategy was developed by Professor Carl Bajema of Grand Valley State University in Michigan. The purpose of paper was to 1) describe Bajema strategy and how it is used in the general genetics course at Ball State University, and 2) discuss how it can be used as a means of identifying students who have misconceptions of the meiotic process that will interfere with their success in learning the basics of Mendelian inheritance. This strategy can be used in secondary school classrooms as a penciland-paper strategy to formatively assess learning. 7. Wyn, Mark A., and Stegink, Steven J. “Role-Playing Mitosis.” The American Biology Teacher (2000). 62(5): 378-381. This article presents a method of teaching mitosis that involves an abstract biological concept, collaborative student problem-solving, and physical involvement with role-play. Role-playing mitosis engaged many senses (auditory, visual, kinesthetic) and it is a concrete method that is easy to conduct and does not require any high-cost materials. This activity may be modified depending on how much material the teacher wishes to cover, and can help clarify problematic terms for students, such as homologous pairs, sister chromatids, centromeres, and so on. Students wear the labels, call out what is happening during the process, and discuss the activity as it progresses. The study found that classes that used the strategy of role-playing mitosis performed better classes that did not include this type of instruction. Students were also more enthusiastic about learning the concept, and could realize the logical sequence of events that occurs during cell division.