What should teachers do to ensure a student construct meaningful understanding in cell division and reproduction concepts? This research examined the effect of 5E learning cycle on 10th grade students' understanding of cell division and reproduction concepts and their alternative conceptions on these concepts. Mixed methods research design was utilized for this aim. Eight classes with 228 students from two public high schools were selected conventionally. Experimental groups received learning cycle (LC)a nd control groups received conventional teaching (CT) throughout the 70 weeks. A three-tier diagnostic test was administered to both groups as pre and post-tests. After the treatment, 12 students were interviewed semi-structurally. The results revealed that learning cycle is superior to conventional teaching on promoting conceptual change along with increasing understanding. The present research recommends teachers utilize learning cycle to improve students' understanding and remediate their alternative conceptions.