Cells are often described as bags of chemistry—but they are better understood as finely tuned physical systems. Within each one, DNA is packed into nanoscopic volumes, enzymes race at turnover rates rivaling jet engines, and molecular collisions happen billions of times per second. This session explores the cell as a physical object—its limits of size, speed, and efficiency. How fast can information move from genome to protein? How does diffusion constrain cell size and shape? How do energy flows through metabolism define what life can and cannot do? By examining the physics that underpins biology, this session challenges us to see cells not as mysterious black boxes, but as programmable systems operating under universal rules. This perspective may hold the key to engineering biology with the same rigor as physics and computer science.