Application of Blended Online-Offline PBL Teaching Model in Undergraduate Molecular Biology

Aiming at the challenges of abstract concepts and insufficient practical ability cultivation in undergraduate molecular biology teaching, this study adopted a cross-cohort continuous improvement design to compare the teaching effects between the traditional teaching cohort and the blended PBL teaching cohort of biotechnology majors. The PBL-cohort implemented a three-stage blended PBL model of "pre-class online exploration-in-class offline collaborative problem-solving - post-class practical extension", with targeted PBL questions designed around core modules. Results showed that the PBL-cohort achieved a significantly higher final exam score. Questionnaire surveys indicated that the PBL-cohort students perceived improved self-directed learning abilities, and recognized the model's value in knowledge application. Additionally, the pass rate of the subsequent Genetic Engineering course was also high in the PBL-cohort. In conclusion, the blended online-offline PBL model effectively enhances molecular biology teaching outcomes and provides an ethically compliant practical pathway for science curriculum reform.