Many high school biology courses address mainly the molecular and cellular basis of life. The complexity that underlies the most essential processes is often difficult for the students to understand; possibly, in part, because of the inability to see and explore them. Six simple practical experiments on purine catabolism as a part of a biochemistry course for 16-18 years students that require only simple equipment for thin layer chromatography have been developed, tried, and tested. These include detection and measurement of enzyme activities in biological extracts, detection of reversible and irreversible reactions, creating a pathway from consecutive reactions. They focus on purines because of their multifunctionality in biochemical processes. They allow students to grasp specific concepts and to use them as a framework for approaching metabolic complexity.