All biological systems are subject to regulation; in recent years, we have come to understand a great deal about a wide range of regulatory systems. This course, which will explore the biochemical mechanisms by which regulatory molecules control cellular processes, is designed to provide a synthetic view of regulatory events in the living cell. Topics will include the cell cycle; cell signaling; mechanisms of action of regulatory molecules; and the molecular mechanisms of cancer, with the aim of describing cancer as a derangement of normal regulatory events that control cell growth, division, and differentiation. Class discussions will focus on readings in the original literature. Format: discussions, three hours a week. Evaluation will be based on class participation and short papers. Prerequisite: Biology 202. Enrollment limit: 2 sections of 12 each (expected: 2 sections of 12 each). Open to juniors and seniors, with preference given to senior Biology majors who have not taken a 400-level course.