Teaching the Cell topic in junior high schools involves a host of problems. The study reported in this paper investigated the effect of various teaching methods on Israeli students' achievements, acquiring laboratory skills, and the dimensions of learning activities. The Cell topic was taught to an experimental group using the Jigsaw method and cooperative learning strategies and to a control group using the customary frontal method. Research instruments included the achievement test on the cell topic and observations before and during the learning activity. Results indicate that students who studied by the Jigsaw method had higher achievement in the test than students in the control group and high achievements were obtained with students with medium academic ability. In classes that improved greatly in academic achievements, the cooperative learning activity increased and positive attitudes towards the Jigsaw method were found. This study recommends developing additional study units in biology for junior high schools as a way to improve academic achievements as well as laboratory skills. Contains 12 references. (Author/JRH)