In this work, we discuss the importance of underlying theoretical assumptions in research, focusing on the conclusions reached when analyzing data from a misconceptions constructivist (stable, unitary) perspective in contrast to a fine-grained constructivist (resources, knowledge-in-pieces) perspective. Both frameworks are rooted in the idea that students construct knowledge based on experiences, but differ in terms of assumptions about the nature and structure of knowledge. Importantly, we argue that misconceptions constructivism and fine-grained constructivism represent different models that can be used to draw conclusions about student reasoning in order to modify instruction. To this end, we present the results of a qualitative study that focused on how students reasoned graphically, analyzing biochemistry student exam responses (n = 50) using both the misconceptions constructivist framework and the fine-grained constructivist framework. The prompts analyzed were two open-ended exam questions administered in a biochemistry course, with the questions requiring students to draw conclusions about rate and reason about how graphs (such as a typical Michaelis-Menten plot) are constructed. As part of this work, themes emerged related to (1) alternative conceptions for reaction rate, reaction order, and Michealis-Menten plots (misconceptions constructivist interpretation), as well as (2) perceptual cuing that lead students to attend to less relevant surface features (fine-grained constructivist interpretation).