Name of teaching material
Models of chromosomes for learning cellular division (made with craft cord and snap buttons) self-made product
Japanese Page URL
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| Target |
Students in junior high school and high school The model was developed and used for students with visual impairment but can be used for any student. |
|---|---|
| Disability category | visual impairment deaf and hard of hearing physically challenged health impairment speech and language disorder developmental disabilities deaf-blind |
| Teaching units / Applicable scenes | science |
| Specific purposes |
The models help students: ・ Understand how chromosomes move during cell division ・ Understand the differences between somatic cell division (mitosis) and meiosis ・ Understand the significance of meiosis |
| Considerations for disability characteristics |
Touching the models assists students with visual impairment, who cannot watch videos, learn about chromosomes. By touching the models, students can learn the information that cannot be transmitted via tactile graphics, such as how chromosomes move, how cell division takes place, the differences between mitosis and meiosis, and significances of meiosis. For the purpose, it is essential to prepare one set for each student. It may be better to start not by explaining everything but by 1) asking students questions so that they think and express their opinions, 2) summarizing them, and then 3) finalizing with explanations. |
| Expected effects and results |
The models are expected to help students: ・ Acquire correct knowledge on what is to be learned ・ Cultivate active attitude toward learning |
| How to use |
(1) Hand out one set of models to each student. Each set consists of four pairs of homologous chromosomes. The colors of the cord used to make the chromosomes are different between students to help teachers detect when the models are mixed up between students and correct them. (2) Ask students questions that induces students to make discoveries, such as “Have you noticed something?” and “How many chromosomes are there?”. Ask “Which is one chromosome?”. After listening to their answers, explain them that each of the X-shaped structures represents a chromosome immediately before cell division, i.e. having a double amount of DNA compared to normal times, and that each of the snap buttons represents a centromere. (3) Lead students to recognize that there are chromosomes that are identical to each other, i.e. having the same length and the centromere at the same position. After they notice it, teach them that such pairs are called “homologous chromosomes”. (4) Tell students that the number of chromosomes in somatic cells is expressed in 2n. (5) During the anaphase, or the fourth phase of mitosis, the chromatids (modeled by pieces of cords mutually attached by a snap button) of each chromosome are to be separated by unfastening the snap buttons. Ask students to put one of the chromatids on the right side of the desk and the other on the left. (6) To explain metaphase 1 of meiosis, ask students to align the homologous pairs of chromosomes (synapsis). Then, ask students to move one chromosome of each homologous pair to the right side of the desk and the other to the left without unfastening the snap button. Ask “When does the number of chromosomes halve?”. Later, explain anaphase 2 of miosis by asking students to unfasten the snap buttons and move one of the chromatids to the farther part of the desk and the other to the nearer side. This is just an example of using the models. Questions can be altered depending on how students respond, which may result in different lesson procedure. Instead of asking students to making pairs of homologous chromosomes, the author asks them “How should we separate the eight chromosomes in order to make 2n=8 into n=4?” and lets students think by touching the models and discussing with mates. Such a lesson helps students naturally understand that the pairs of homologous chromosomes need to be separated in order to equally divide the chromosomes. |
| Related teaching materials and information | TAKEI Yoko. Teaching cells in junior high and high school science (in Japanese), Shikaku Shogai Kyoiku Booklet (Visual Impairment Education Booklet), Vol. 13 (2010), pp. 30-37 (Edited by Shikaku Shogai Kyoiku Booklet Editorial Board, Special Needs Education School for the Visually Impaired, University of Tsukuba, and published by The Earth Kyoikushinsha) |
| Useful for other students | The models are also useful for students without impairment. In such a case, one set of models for two students may be sufficient. |
- Informant TAKEI Yoko, Special Needs Education School for the Visually Impaired, University of Tsukuba
- Keywords cell division, chromosome, mitosis, meiosis
- Created 2025-02-05 15:44:07
- Updated 2025-02-05 15:44:07