Debunking Key and Lock Biology: Exploring the prevalence and persistence of students’ misconceptions on the nature and flexibility of molecular interactions 

Diagnostic of students' misconceptions using the Biological Concepts Instrument (BCI): A method for conducting an educational needs assessment

“…The answers to question 15 (How does a molecule bind to its correct partner and avoid “incorrect” interactions?) revealed that many (~61%) Gymnasium students shared the misconception “Correctly bound molecules fit perfectly, like puzzle pieces”, a choice that is likely to be the result of teaching students through the use of a “key and lock” analogy, which makes evolutionary modification all but impossible [ 54 ] Interestingly, this answer is still chosen by 30% of students even after 2 years of biology studies at two Swiss universities [ 54 ], indicating that the physical and chemical foundations of molecular interactions are not well appreciated by students even after extended physics and chemistry instruction. In question 16, students were asked to explain the dissociation of molecules.…”

“…Previous results demonstrated that such misunderstanding is still found even after 2 years of undergraduate education at university [54]. Students’ understanding of how conformational and physicochemical properties of DNA and molecular movements are involved in molecules “finding” each other, interact and come apart (interaction specificities and stabilities / half-life) seems weak.…”

“…As considered above, most participants underestimated or dismiss the role of stochastic events as the driving motion of molecules and many other biological processes. Previous results showed that only ~49% of 2nd-year undergraduates studying biology at two distinguished Swiss universities have selected the best answer, “Random movements would bring it to the ATP synthase” in question 20 ( Fig 4 ) [ 54 ]. Odom and Barrow [ 38 ] have revealed, through the use of the Diffusion and Osmosis Diagnostic Test (DODT), that many students are attracted by answers underlying an anthropomorphic view of matter such as "the molecules want to spread out" or "there are too many particles crowded into one area and therefor they move to an area with more room".…”

“…We observed some important misunderstandings of how DNA structure facilitates the storage of genetic information and how a failure to appreciate the dynamics of molecular interactions can be traced back to missing knowledge on the importance of physical and chemical properties of molecules. Previous results demonstrated that such misunderstanding is still found even after 2 years of undergraduate education at university [ 54 ]. Students’ understanding of how conformational and physicochemical properties of DNA and molecular movements are involved in molecules “finding” each other, interact and come apart (interaction specificities and stabilities / half-life) seems weak.…”

“…An obvious approach to more efficient curriculum design is to first assess student needs by identifying areas of problematic understanding (known as “needs assessment” in management terminology) [ 21 ]. The results from this and other applications of the BCI [ 54 ] have stimulated an initiative to rethink the biology curriculum with respect to the educational needs students have when entering university. For example, the introductory biology course (“Grundlagen der Biologie 1A”) has been refocused to concentrate on key concepts of biological systems, from the chemical and physical properties of molecules and cells to genetics and gene expression.…”