Many science educators are concerned with students' ability to understand science as a process and with their conceptions of scientific knowledge. Preliminary work has shown that the use of a model organizer can result in student perceptions of improved understanding, but the reason for this effect is not known. This research was undertaken to determine whether students' conceptions of models and the model building process could be useful as an organizer for understanding scientific knowledge and process. Subjects were 687 undergraduate general biology students at a comprehensive southwestern university. These students were asked to respond to two similar sets of six statements referring, respectively, to models and model building or scientific knowledge and process. Responses were reduced to a manageable number of descriptive propositions and analyzed. Results indicated that relationships describing the artificial nature of models could be useful if transferred to the students' conception of scientific knowledge. Such an organizer could be counterproductive in other areas, however, if instruction was not given to expand students' awareness of the full range of models and the process of model-building. Students' knowledge of models was less extensive than might have been expected or desired for individuals at this educational level and this points up a possible weakness in the current science curriculum. (Author)