Lecture, three hours. Enforced requisites: courses 105A, 110A, 115A, Chemistry 110A, Molecular, Cell, and Developmental Biology 100 (or M140 or 165A). Equilibrium phenomena. Application of basic mechanics, optics, and thermodynamics to biological design: structure of skeleton, scaling of bone and muscle mass, swim bladders, and animal vision. Application of elementary statistical physics, electrostatics, and elasticity to structure of proteins, DNA, and biomembranes. Concurrently scheduled with course C287A. P/NP or letter grading.