An enzyme exercise to address the problem of students inability to visualize chemical reaction at the molecular level is described. This exercise is designed as a dry lab exercise but can be modified into a classroom activity then can be augmented by a wet lab procedure, thereby providing students with a practical exposure to enzyme function.

Provided are directions for culturing bacteria by using yoghurt as a culture medium. Yoghurt is a safe medium and results in an end product which may be eaten if desired. (PB)