Purpose of Study: The aim of this study is to investigate the nature of pre-service biology teachers' metaconceptual processes that were active as they participated in metaconceptual teaching activities. Methods: Several instructional activities, including poster drawing, concept mapping, group and class discussions, and journal writing, were carried out to activate the metaconceptual processes of 32 second-grade, pre-service biology teachers in order to change their alternative conceptions regarding seed plants. Case study was used as a research method. Among the 32 participants, five participants who activated rich and diverse metaconceptual processes and who reflected well and clearly on their mental processes in their journals were selected for the case study. The journal entries written by these five students before, during, and after the teaching activities were used as a data source. Content analysis was used to code the journals of the preservice teachers according to the types and the content of metaconceptual processes. Results and Conclusions: The results indicated that students engaged in several types of metaconceptual activities, which can be classified under metaconceptual awareness, metaconceptual monitoring, and metaconceptual evaluation. Metaconceptual processes were activated interdependently in different forms, ranging from simpler first-order metaconceptual awareness to more sophisticated metaconceptual evaluations. Recommendations: In designing metaconceptual teaching activities, teachers should take the interdependent and multifaceted nature of these processes into consideration.