A lesson plan is a design problem for a teacher. The desired solution to this problem is to design an instructional process that can guide students in constructing an understanding of scientific concepts through their own thinking. This article demonstrates a practical approach to designing an effective lesson plan. The approach has five phases: listing the concepts in a lesson, proposing questions that can be answered by each concept, sequencing the questions according to the logic of student cognitive development, selecting resources and designing tasks to create learning situations, and applying knowledge to scientific research and real life. A meiosis lesson from a high school biology course serves as an example for understanding the solutions to problems that may arise in each phase.