Student Thinking About Metabolic Pathway Dynamics and Regulation

Abstract

In an effort to improve the effectiveness of biochemistry instruction, this study seeks to identify undergraduate students' ideas about biochemical pathway dynamics and regulation, a key concept in biochemistry. Understanding student thinking about metabolic pathways will enable the design of instructional materials that build on students' difficulties and prior knowledge. We probed student thinking using well‐defined problems about metabolic pathways that are unfamiliar to students. We conducted think‐aloud interviews with 22 introductory biology students in Fall 2016 and are currently conducting interviews with 25 biochemistry students. In these interviews, students solve several well‐defined metabolic pathway problems and are prompted to describe the knowledge and strategies utilized during the solution process. Thus, the interviews uncover cognitive processes that are not necessarily revealed in written answers. We analyze think‐aloud interviews using qualitative content analysis and compare the prevalence of and relationships among particular student interpretations, ideas, and problem‐solving strategies.Using Loertscher and colleagues (2014) description of metabolic pathway dynamics and regulation, we categorized biology students' ideas into eight main topics: reversibility, free energy, reaction coupling, metabolic compound effects, understanding of branch points, discussion of flux, enzyme characteristics, and enzyme activity and regulation. We found that biology students frequently recognize reaction reversibility due to the representation of arrows in the problems, but students lack understanding about the reasons for reversibility. Biology students also were able to accurately predict the impact of changes in the pathways on the final products, even if they held non‐canonical ideas about what was happening via feedback, inhibition, and about rates. However, even biology students who arrived at correct conclusions using canonical ideas struggled to accurately describe what was happening to the intermediates in the pathway. While some students were able to recognize the key properties of enzymes, such as reversibility and the lowering of activation energy, many students struggled with mechanisms of the enzyme‐facilitated processes. This indicates to us that students may still be struggling with the core understanding of what an enzyme is and how it acts, which may be limiting understanding of pathway dynamics. Results from biochemistry students are forthcoming, and we expect important differences compared to biology students based on preliminary data.At the conclusion of this study, we will have identified major ideas, canonical and non‐canonical, that biology and biochemistry students draw upon when solving problems about biochemical path dynamics and regulation. These ideas will serve as targets for future research and instructional design.Support or Funding InformationThis material is based on the work supported by the National Science Foundation under grant DRL 1350345This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.