Making the Most of Mitosis

Making the Most of Mitosis

by Trey Smith

“Why not show your students images of mitosis—out of order and without labels and vocabulary—before you ruin it for them?” I posed this question to a new teacher. She was teaching a seventh grade science class during summer school. She had come to me for advice. And the advice I gave her surprised even me.

Teachers like to talk. Teachers like to tell. Teachers like to spoil surprise and wonder, especially in science. Not all teachers are so selfish and dull. But certainly the weight of core curricula and the pressure of standardized tests with single answers can push a teacher to approach learning in a way that crushes questions and smothers opportunities for exploration. I have been in enough classrooms as a student to know what this suppression feels like. So have most students. Too often a teacher’s first inclination, especially in the first years of teaching, might be to provide a set of notes defining a list of the words needed to describe an event in the natural world. The teacher is too often a talking textbook.

The teacher is too often a talking textbook.

Mitosis, the process by which a cell with a nucleus creates two cells with identical sets of chromosomes, presents a ripe opportunity for a teacher to stand and deliver an outlined set of notes about Prophase, Metaphase, Anaphase, and Telophase. The teacher tells students: “Here is what the great scientists have described. Here is what you need to memorize.” The teacher introduces the key concepts; students label a few diagrams and prepare for a test on the material.

When I taught seventh grade three years ago, I devised mnemonic devices to help students remember what occurs inside a cell during each stage of cell division. (“Just think ‘middle’ when you see ‘Metaphase’ to remember where the chromosomes line up.”) I then made memorization more fun with some theater. Students wrote scripts, made props, and acted out the stages to show how cells create copies of themselves. I still have some of the student-created props in a filing cabinet in my room, tokens of what I felt then were excellent and engaging teaching methods. Mnemonic devices and student-created performances constituted a progressive pedagogy, or so I thought. But it was still textbook learning, just dressed up in student choice and some playacting.

But it was still textbook learning, just dressed up in student choice and multiple intelligences.

Three years later, sitting with a pre-service teacher and planning a lesson for her summer school students, I did not mention the skits or the mnemonic devices. Instead, I suggested an approach that I had not attempted in my own classroom. Maybe it was the graduate courses I had taken, the books I had read, a conference I had attended, my work with the Philadelphia Writing Project, my own experiences teaching, or some combination of influences that compelled me to reimagine mitosis in the classroom.

Students should observe cells, at different stages of cell division, without labels and teacher-provided notes. Before scientists named the stages of mitosis, they observed movement and changes inside cells using a microscope, created tentative explanations for what was occurring, and then checked their theories against repeated observations. Might a student, who sees stages of mitosis, be able to describe what is happening to the cell? Could a student put the stages in order based on her predictions about what is happening inside the cell? Would a student even be able to reason through the purpose of the movements of the inner parts of a cell to create a tentative explanation for what is happening?

Onion root tip 400x, Source: Elson, J.A. (2009). http://www.3dham.com/microgallery

A teacher might provide a student with a slide of an onion root tip and a microscope or with diagrams of a cell at different stages. Students could use these images to make notes and generate explanations. A teacher might not mention that there are different stages and instead might ask students what the images represent. A teacher could ask students to put the images in some kind of sequence and describe what the cell is doing. A teacher merely needs to provide the examples or models and students will do the rest. Then, the teacher could encourage students to name phases or compare notes with a nearby group.

Diagram showing the changes which occur in the centrosomes and nucleus

of a cell in the process of mitotic division, Source: Grays Anatomy. (1918).

With a little bit of patience, a collaborative classroom environment, and the right kind of questioning, a class of students almost certainly can devise a tentative description that would explain the process by which cells multiply.

State standards and commercial curricula provide longs lists of topics and content that teachers and students should grapple with. Teachers have (or should have) the space and intellectual freedom to determine how students will grapple with the ideas and questions addressed by standards. Science education literature urges teachers to provide students with learning experiences that reflect the ways in which scientists make sense of the world around us. As I learn more about my craft, I find that students respond to opportunities to reason and wrestle with ideas.

Three years from now, I might file my new mitosis approach away with the scripts and mnemonic devices that I thought were so engaging just a few years ago. Time and experience will bear out what works and what needs improvement. I will experiment in the coming years.

For now, though, my working ideas about teaching mitosis seem promising.

Trey Smith teaches science at Boys' Latin of Philadelphia Charter School. Trey is co-editor of the PhilWP Journal and coordinates publicity and web presence for the Philadelphia Writing Project. Trey joined the Philadelphia Writing Project as a teacher consultant in 2009.