Role-playing the parts of chromosomes and centrioles, learners use large chromosome models and nylon cords (spindle fibers and cell membranes) to walk through the processes of mitosis and meiosis. Physical manipulation of the chromosomes and their parts in the process of cell division and replication both clarifies and reinforces some very abstract concepts for learners. The activity demonstrates crossing over and gene linkage. It may be extended to illustrate chromosome anomalies such as deletions and trisomies. Models can be used to show other mutation types as well as x-linkage. A large floor space is needed for this activity.