The aim of this research was to study the effectiveness of teacher controlled segmented-animation presentation on learning achievement of students with lower level of prior knowledge. Segmented-animation and continuous-animation courseware showing cellular signal transmission process were developed for the research purpose. Pre-test and post-test quasi-experimental design was employed involving a research sample consisting of 124 Diploma in Education students. Data were analyzed by using T-test and Univariate ANOVA. In general, the research finding indicates that teacher controlled segmented-animation which was presented via LCD projector was significantly more effective than teacher controlled continuous-animation presentation in enhancing students' learning performance. Apparently, the segmented-animation had helped students in extracting necessary information in order to develop a more accurate mental model of the process implied by the animation. The development of accurate mental model is important for the formation of perfect schema to be registered and retrieved from long-term memory structure for successive learning. (Contains 4 figures.)