John L. Tymoczko was Towsley Professor of Biology Emeritus at Carleton College, where he taught from 1976 until his death in 2019. He taught a variety of courses, including Biochemistry, Biochemistry Laboratory, Oncogenes and the Molecular Biology of Cancer, and Exercise Biochemistry, and cotaught an introductory course, Energy Flow in Biological Systems. Professor Tymoczko received his B.A. from the University of Chicago in 1970 and his PhD in Biochemistry from the University of Chicago with Shutsung Liao at the Ben May Institute for Cancer Research. He then had a postdoctoral position with Hewson Swift of the Department of Biology at the University of Chicago. The focus of his research was on steroid receptors, ribonucleoprotein particles, and proteolytic processing enzymes.