The Massachusetts Institute of Technology (MIT) produces BLOSSOMS (Blended Learning Open Source Science or Math Studies), a series of instructional videos designed to enhance high school math and science instruction. In this video, Natalie Kuldell, a professor in MIT's Bioengineering department, leads a classroom activity designed to help students understand the concept and processes of protein purification. The majority of this fifteen-minute video is designed to be shown to students during a single class period. Dr. Kuldell describes the potential uses for protein purification in fields of medicine and engineering. Next, she provides clear instructions for group activities designed to help students draw on their background knowledge about cell types and brainstorm potential methods for protein purification. (The video pauses to provide students with a chance to work on assignments, simulating the experience of a guest teacher). At the end of this video, Dr. Kuldell provides suggestions to instructors about where to situate this single lesson in a science curriculum and possible lesson adaptations.