In this article we recount our experiences of teaching photosynthesis in an integrated way to secondary school students and teachers, science undergraduates and postgraduates. Conceptual questions were posed to investigate learners' fundamental understanding of simple light-dependent and light-independent processes taught to most students at secondary level and beyond. We found that students did not grasp main concepts and could not apply basic knowledge to answer simple questions about photosynthesis even after multiple exposures to the topics. We attribute these shortcomings to rote learning and master-disciple relationship generally practised in Thailand. We propose here a change of emphasis from teaching to learning, especially, self-learning, collaborative learning, self-reflection and integration of knowledge by self. Corrective suggestions are given about changing the common practices of teaching/learning with a cognizance of the present and future era of easy access to electronic information and globalization where life-long learning, problem solving skills, originality and creativity hold keys to success.