The authors of this article applied the determination of phenolic and flavonoid content in small berries to create a didactic cycle based on student-centered active learning (SCAL) in which students actively participated in the topic while studying and profile-forming as future biology and chemistry teachers. The fundamental part of the proposed didactic cycle is that students solve the following task: Determine the phenolic and flavonoid content in berries ("Vaccinium myrtillus" L., "Vaccinium vitis-idaea" L., and "Vaccinium corymbosum" L.) in your region. The submitted interdisciplinary topic is relevant to everyday life, and it aroused interest and enthusiasm among students. The students had the opportunity to test their theoretical knowledge in practical experimental research, and they attempted to work as researchers.