The interaction between light and different biological systems represents a crucial phenomenon in biology and is notably responsible of many fundamental outcomes related to signaling as well as  nergy conversion and storage. Light is indeed essential to assure life as we know it. On the other hand, light may also represent an external stress producing harmful effects related most notably to  skin cancer development.
In this talk, through a series of examples mostly related to DNA photolesions induction and repair and rhodopsin photosensitization, we will illustrate the crucial role played by molecular modeling and simulation in elucidating such processes. We will also stress the need of tackling multiscale phenomena taking into account at the same time complex electronic structures and their interplay with dynamic sampling and time evolution in complicated biological macrostructures.
By using appropriate and high-level molecular modeling and simulation strategies we will prove that the scientific field is nowadays ready to provide answers to, and hence rationalize, biological  questions related most notably to mutation, DNA replication, cell resistance to stress, or cell signaling.
Hence, we will prove that we are clearly leaving the age of the simulation in model systems to enter into the age of a veritable in silico photobiology.

References
1. Francés-Monerris et al. (2018) Chem. Sci. 9, 7885.
2. Dehez et al. (2017) Nucleic Acids Res. 45, 3654-3662
3. Bignon et al. (2017) Nature Sci. Rep. 7, 8885
4. Gattus et al. Phys. Chem. Chem. Phys. 19, 23187
5. Gattuso et al. (2016) Phys. Chem. Chem. Phys. 18, 18598
6. Bignon et al. (2016) Nucleic Acids Res. 44, 8588
7. Gattuso et al. (2016) J. Phys. Chem. Lett. 7, 376
8. Francés-Monerris et al. (2018) Phys. Chem. Chem. Phys. 20, 25666
9. Semmeq et al. (2019) Chem Eur. J. doi: 10.1002/chem.201902462
10. Hognon et al. (2019) J. Phys. Chem. B 123, 7365
11. Francés-Monerris et al. (2019) J. Phys. Chem. Lett. 10, 6750
12. Hognon C. et al. (2019) J. Phys. Chem. Lett. 10, 72000
13. Marazzi et al. (2019) J. Phys. Chem. Lett. 10, 7133