From an expert point of view, misconceptions are false solutions a student develops as a response of hypotheses. Misconceptions have varied sources and different intensities of the way they govern the mental model of student mind. These, could determine different actions a teacher develops to help students to overpass them. During the implementation of an optional named „Elements of Biophysics” to 17-18 years old students, I identified different kinds of misconceptions. Two of these are evoked in this work, one as a result of the extrapolation of calculus developed during a learning experience, the other one as a lock of enough information the student has to develop a hypothesis. The way I succeeded in surpassing these misconceptions was also resumed. Even if many works determined lists of physics misconceptions established for students of different ages, the integrated optional - the optional as a new discipline - is not the case. In these situations, only the teacher’s experience is the main factor in the success of misconceptions identification, as a first step to theirs exceed.