Biochemistry instructors often use external representations--ranging from static diagrams to dynamic animations and from simplistic, stylized illustrations to more complex, realistic presentations--to help their students visualize abstract cellular and molecular processes, mechanisms, and components. However, relatively little is known about how students use and interpret external representations in biochemistry courses. In the current study, variation theory was used to explore the potential for student learning about protein translation from a stylized, dynamic animation. The results of this study indicate that students learned from this animation, in that they noticed many critical features of the animation and integrated those features into their understandings of protein translation. However, many students also focused on a particular feature of the animation, the Shine-Dalgarno sequence, that their instructors did not feel was critical to promote an overall understanding of this metabolic process. Student attention was focused on this feature because of the design of the animation, which cued students to notice this feature by significantly varying the appearance of the Shine-Dalgarno sequence.