To develop an understanding of mitosis.
Students have been taught at an early age that the cell is the building block of life, and have most likely used a simple microscope to view cells in elementary school. They have been introduced to the idea that organisms depend on cell division to pass the genetic information from one cell to the next, but how this is accomplished is still a mystery. They are now ready to understand the concept that one cell is capable of making an exact copy of itself.
This lesson will introduce students to the step-by-step phases of mitosis in an effort to imprint on the young mind the idea that each cell is highly organized. Prior to this lesson, students should have discussed both plant and animal cell structures. If they haven't, focus students solely on animal cells throughout the lesson.
Students will use the Mitosis app for this lesson. You may want to make sure it is installed on your classroom mobile devices (iPods or iPhones) before you begin the lesson.
In this lesson, students will make physical representations of mitosis. Read the activity ahead of time and choose appropriate materials for your class.
Students will also develop and perform a skit about the phases of mitosis. The props needed for this activity will depend on your students' ideas as they create the skit.
Help students focus on cell division by asking questions such as:
- Has your body changed in the past six months?
- How did you recognize this change?
- Are you taller? Did your hair grow? Did you clip your toenails?
- Has anyone broken a bone recently?
- How does your body repair itself?
(Answers may vary. Accept all answers and encourage students to explain their answers.)
Say to students: We are going to investigate the process by which cells make exact copies of themselves. Bone cells repair bone cells, hair cells cause your hair to grow, and new fingernails grow to replace broken ones. Practically every cell in your body is capable of making a copy of itself through the process of mitosis. Plant cells replicate by mitosis as well. There is another process by which living things make an entirely new organism, but that won't be discussed in this lesson. We will focus on plant and animal cells making exact copies of themselves.
Introduction to the Phases of Mitosis
Before students use the Mitosis app, they can learn more about it by using their Mitosis student esheet to go to the Mitosis App tool, which will provide them with information on how to use the app.
Students should use their mobile devices to go to the app. Once in the app, students should tap on "Images," which will take them to a page with two slide shows. They should tap on the "Immunofluorescent stains of a dividing cell" slide show, which shows students the five stages of mitosis. You should follow along with students and briefly explain each stage. (Using a presentation station simplifies this task.) Ask students to identify the cell parts they recognize when appropriate.
Go through the slide show again, instructing the students to draw and take notes on each of the five stages on their Mitosis student sheet. Next to each picture, students should write the name of the stage it depicts.
To learn more as well as to check for understanding, students should use their esheet to view the Mitosis Animation on the The Biology Project website (the animation is at the bottom of the page.)
You can display the animation yourself, clicking through each picture, pausing for discussion. Ask students to describe what is happening in each image.
Creating a Physical Representation of Mitosis
In this part of the lesson, students will create physical representations of mitosis on poster board, using a variety of the materials listed in the Materials section (e.g., yarn to represent chromosomes, lifesavers to represent centromeres).
Students should divide the poster board into five sections (one for each phase of mitosis) and use what they have learned to depict each phase. Students may work independently or in pairs to illustrate the mitosis of a plant or animal cell, with the shape reflecting the type; plant cells should be rectangular, and animal cells should be more circular.
You may give specific instructions to the students, or set them free and let their creative juices flow! Students can follow the instructions on the student sheet.
After all the posters have dried, display them around the class in a "Mitosis Gallery." Ask students to help with the display and divide the posters into two groups based on the cell type.
To check for understanding, students should draw a flow chart depicting a cell going through four rounds of mitosis (rather than just one, as in their posters). Students should realize that four rounds of mitosis would lead to 16 cells.
Students should write and perform a skit to show the process of mitosis, using the loose guidelines that follow. These guidelines are intended to help get you started, as well as provide room for the development of a skit that suits your class size, available supplies, and students' creativity.
Tell students that they need to write a "scene" representing each phase of mitosis. They should refer to the posters they created to determine the essential "characters," as well as what the characters should be doing in each scene. In addition, students should create a narrator(s) role, which will explain the processes as they are happening in the skit.
Following is a sample scene, representing Metaphase:
When the narrator calls out "Metaphase," the chromosomes meet in the middle of the imaginary cell. The students playing centrioles walk into the center of the cell and hand the students playing chromosomes a piece of yarn. This represents the spindle fibers attaching to the chromosomes. While holding the other end of each string, the students playing centrioles walk to opposite ends of the imaginary cell to prepare for anaphase.
Following are ideas for props to be used throughout the skit:
- A circle of students could hold plastic wrap to represent the cell membrane.
- A small group of students could hold bright colored construction paper to represent the nuclear membrane.
- Students could hold oval-shaped construction paper to represent chromosomes; they could use two pieces, one behind the other, which can be separated in prophase when chromosomes duplicate and begin to form an "X."
- Yarn can be used to represent spindle fibers.
Again, structure this activity to meet the needs of your students. It can be as simple or elaborate as you'd like, but should allow students the opportunity to refine and demonstrate their understanding of mitosis.
Ask students to respond to this statement in their science journals:
Pretend you are a theater critic and your job is to write a review of the Mitosis Skit for the school newspaper. Write a brief review that includes at least these points:
- How the skit represented the process of mitosis;
- A review of the players of mitosis (e.g., cell membranes, chromosomes); and
- Thoughts on how this skit could be improved to better represent mitosis (focusing on the science of mitosis).
Slides of mitosis in onion root tip cells can be found on the Molecular Expressions website. This could be used after students have looked at onion root tip cells under a microscope.
The Molecular Biology Notebook could be used to extend ideas in this lesson.