"Soft condensed matter" also includes biomaterials and living matter. Using modern optical spectroscopy (high resolution Brillouin scattering, ellipsometry, synchrotron radiation) we investigate low-frequency fluctuations of protein conformations in solution and in the crystalline state as well as elastic properties of biopolymers such as DNA. Particular interest is on the molecular features and the biologival relevance of the strong overstretching of DNA molecules.