Different genres of scientific articles have begun to diffuse into science curricula. Among them, adapted primary literature (APL) retains the characteristics of scientific research articles, while adapting their contents to the knowledge level of students in the 11th to 12th grades. We present three models for the teaching and learning of the opening sections of an APL article by three different biology teachers. Each of the teachers used a different model for "stepping into the unknown" of the article. The analysis of the teaching approach of the opening sections of an APL in the classroom illustrates the challenges presented by the use of scientific articles for learning and instruction and the strategies that might be useful in overcoming them. By comparing those models for the APL article, we aim at facilitating the use of different genres of scientific articles in class, and promoting the design of additional teaching/learning models. (Contains 1 table.)