Understanding Photosynthesis and Cellular Respiration: Encouraging a View of Biological Nested Systems

Connecting plant processes on multiple ecological levels has shown to be exceptionally challenging for learners. Decades of research suggest that learners are challenged in their conceptions of photosynthesis and plant cellular respiration. These processes include multiple biochemical steps, occur simultaneously within plant cells, and share common molecular components. Learners often compartmentalize functions without considering the interconnections of the processes within and across multiple system levels. Understanding connections among biological systems at macro, micro, and symbolic levels is important for biological literacy. Given that photosynthesis and cellular respiration impact multiple system levels, implications exist for those educators who traditionally emphasize only the biochemical level to address these processes. This chapter presents two individual cases and one summary case of preservice teachers who uniquely described their conceptions about photosynthesis and cellular respiration and the connections between these two processes. Pedagogical implications and strategies are discussed which include multiple representations to scaffold student thinking across biological levels.