Threshold concepts can be identified for any discipline and provide a framework for linking student learning to curricular design. Threshold concepts represent a transformed understanding of a discipline, without which the learner cannot progress and are therefore pivotal in learning in a discipline. Although threshold concepts have been identified for biology and work has begun on identification of threshold concepts in chemistry, threshold concepts unique to biochemistry have not been characterized. Biochemists generally agree upon a set of essential core concepts for the discipline, but not all core concepts meet the criteria of threshold concepts. Work on threshold concepts in biology provides a starting point for thinking about possible threshold concepts in biochemistry. For example, the ability to think correctly about scale, submicroscopic events, and energy transformations are biology threshold concepts that may also be relevant for biochemistry. The primary purpose of identifying threshold concepts in a discipline is to provide a starting point for effective curricular design that is likely to result in the greatest improvement in student learning. Because of the importance of threshold concepts in mastery of a discipline, it is reasonable to expect that if more time were spent developing threshold concepts early in the study of a discipline, the learning of additional core concepts would happen more quickly and student understanding of core concepts would be deeper. Therefore, as ongoing efforts to identify core concepts and big ideas in biochemistry move forward, a focus on threshold concepts will help biochemistry educators focus their teaching on strategies that promote transformative learning and provide a strong foundation for continued growth.