The purpose of this research was to determine the effect of the 5E model on the understanding of the molecular genetics concepts taught in general biology. The research had a quantitative focus and a quasi-experimental design, and the participants were 40 undergraduate students from a private university in the west of Puerto Rico, which were divided in two control groups and one experimental group. The initial data was obtained through a pretest that measured the understanding of molecular genetics concepts. The treatment lasted six weeks and consisted of the instruction of the topics of DNA structure and replication, transcription, translation, and mutations. The after-instruction understanding of the concepts was evaluated through a posttest. The results showed that the 5E model had a significant effect (p < 0.05) in generating a higher understanding of the concepts presented.