It is essential that biology and chemistry students have the skills to both visualize and interpret chemical reactions.  As students gain experience within the discipline, they build connections between new knowledge and their prior knowledge. For example, students are taught mechanisms in organic chemistry, and then later in their coursework they are challenged to apply that knowledge of chemical reactions to biological systems in biochemistry.  This study explores how biochemistry and organic chemistry students identify and describe nucleophiles and electron movement within the context of the serine protease mechanism, which catalyzes the hydrolysis of a peptide bond. Using eye-tracking, we measured how 17 organic students and 14 biochemistry students engaged two-dimensional representations of chemical reactions. Participants were asked to identify chemically reactive groups, identify nucleophiles, and evaluate electron movement at various steps in the serine protease hydrolysis reaction using a Tobii X3-120 eye tracker. After the task, students were engaged in a retroactive think-aloud (RTA) interview, in which they watched their eye movements and explained their thought process as they were completing the tasks. During the RTA, students were also given a portion of the mechanism and asked to draw the arrows showing the electron movement between the given reactants and products. RTA interviews were transcribed and coded, and the eye tracking activities were analyzed based on fixation counts and durations as well as general path patterns. These data were compiled for students who were currently enrolled in either organic or biochemistry courses, and then the two sets compared against one another. Preliminary results suggest biochemistry students were more efficient than organic students at identifying nucleophiles. Both groups of students held similar definitions for nucleophiles and similar approaches for evaluating and representing electron movement.

Comparing organic and biochemistry students approaches to identifying nucleophiles and electron movement

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.