We have developed and implemented a serial experiment in molecular cloning laboratory course for undergraduate students majored in biotechnology. "Pseudomonas putida xylE" gene, encoding catechol 2, 3-dioxygenase, was manipulated to learn molecular biology techniques. The integration of cloning, expression, and enzyme assay gave students a chance to mimic real research and product development by connecting separated techniques. This serial experiment helped students set up intact idea of molecular biology and to understand the relation of each individual operation. (Contains 6 figures and 2 tables.)