Making sense of ATP hydrolysis: how students reconcile conflicting ideas from chemistry and biology.

Energy is a core concept across STEM, but disciplinary differences in how the topic is taught can lead students to develop a fragmented understanding. One well-documented misconception is that "breaking bonds releases energy," a belief especially common when biology students reason about adenosine triphosphate (ATP) hydrolysis. Using Hammer's resources framework, we investigated whether students' misconceptions about exothermic bond breaking stemmed from a failure to activate chemistry knowledge in a biology context, or from a complete absence of that knowledge. We conducted semi-structured interviews in which introductory biology students first explained why ATP hydrolysis releases energy and then chose the reaction coordinate diagram that best represented the process. Initially, most students claimed that ATP hydrolysis releases energy because bonds are broken. However, when prompted with a reaction coordinate diagram, one third of students spontaneously corrected themselves, realizing that breaking bonds requires, rather than releases, energy. These results suggest that even when introductory biology students make errors in chemical reasoning, many actually possess the relevant underlying knowledge (e.g., "breaking bonds requires energy") but fail to activate it in a biology context.