Engaging undergraduates in research is essential for teaching them to think like scientists, and it has become a desired component of classroom and laboratory instruction. Research projects that span an entire semester expose students to a variety of concepts and techniques and allow students to use experiments to learn scientific principles, understand why specific techniques are applicable, critically analyze varied data, and examine how experimentation leads to acquiring knowledge. To provide an experience with these features, a semester long research project was integrated into a combined lecture and laboratory course, Molecular Biology. The project utilized the zebrafish model to examine gene expression during embryonic development and required students to develop and test hypotheses about the timing of expression of previously uncharacterized genes. The main goals for the project were to provide opportunities for students to develop critical thinking skills required for conducting research and to support the content goals of the course. To determine whether these goals were met, student performance on the steps of the project and related pre-test and post-test questions was examined.