Monday, April 2, 2012

Modeling Mitosis

Mitosis is a confusing process if you learn about it without context.  When you think about it critically, however, each step has a clear purpose.  In order to improve our understanding of mitosis and how it occurs, we decided to model it live in class.

Each student was assigned a role as either cell membrane, centriole, chromosome, or nucleus.  In our class, we have 10-11 students, so we selected one nucleus, four students to help with the cell membrane, three students for chromosomes and two centrioles.  These numbers can be adjusted as needed, or several cells can be modeled. 

At first, we set up a "cell" on the floor with jumprope acting as cell membrane, a large laminated paper disc as the nucleus, laminated pictures of centroles, and chromosomes.  The chromosomes were also made of laminated paper, but I created them so that they velcro together on the centromere and can be pulled apart during a later phase.

(I made several colors of the model below.  I cut them out, then put velcro dots on the centromere so that they can connect together, then tear apart when necessary.)

Once students were sorted with their roles and had their handouts showing the phases of mitosis, we began our simulation.  First, the genetic material in the nucleus bundled together into chromosomes.  The centrioles then move to the far sides of the cell and begin to form spindle fibers (modeled by yarn) that extend towards the nucleus.  As the nucleus dissolves, the chromosomes line up in a row in the middle of the cell.  Each spindle fiber grabs onto one half of a chromosome, then pulls the halves of the chromosomes over to the sides of the cell.  At this point, two nuclei form in either side of the cell and the cell membrane students begin pinching in and creating two separate cells. 

We had to practice this a few times in order to get it right, but after a few tries, we were able to go through the whole process with little direction from teachers.  Overall, it was a fun way to get up out our seats and model a process in action!


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