TRADITIONAL METHODS AND MATERIALS for teaching and learning at the college and university level often fail to satisfy both teacher and student. In order to create a more interactive learning environment for students in a biochemistry course at the University of Virginia, a series of exercises, written in Java, has been designed to explore, communicate, and test various aspects of the biochemistry curriculum. Java is a cross-platform, object-oriented computer language that is ideally suited for either stand-alone applications or Web-based programs called applets. Because the Web offers significant advantages of accessibility, the exercises described here have been written as applets. Each applet is focussed on a particular topic or aspect of the course content, and provides an interactive exercise that is suitable either for in-class demonstrations by an instructor or out-of-class problem solving by students. The Java language is ideally suited for these purposes. Its graphical user interface capabilities are versatile enough to create and display any imaginable pedagogical scenario, combining attractive graphic displays with rich interactive decision-making opportunities for the teacher and/or student. Examples of applets designed for introductory biochemistry include interactive amino acid titrations, calculations of amino acid titration behavior, analysis of alpha helices in proteins using a scrollable helical wheel, enzyme kinetics analysis, and a series of enzyme mechanism tutorial exercises. The ability of Java to interact with other software tools is demonstrated by the design of a Ramachandran plot applet that interacts with and controls a virtual reality (VRML) scene of a pair of rotating peptide planes using an External Authoring Interface (EAI).