BIOL 1202 Lecture Notes - Lecture 1: Photosynthetic Pigment, Reactive Oxygen Species, Melanin
Document Summary
It is a source of energy, and information. If the energies don"t match, then the photon of light is not absorbed but instead is transmitted through the molecule or reflected. Light energy must be absorbed by molecules called pigments. Wavelength: distance between two successive peaks - determine color. Ionizes biological molecules, which affects their structures and functions. Too energetic, it excites electrons, but can also knock electrons off atoms. Ozone partially absorbs uv radiation, therefore not all wavelengths make it to. Melanin: melanin synthesis increases when skin cells detect dna damage caused by uv light. Darker skin produces more melanin compared to lighter skin. Skin reflectance: the amount of uv light that reflects off, rather than is absorbed by, the skin. It is lowest at the equator, increases towards poles. Uv - a (315 - 400 nm) o o. Penetrates into the skin where it generates reactive oxygen species. Uv - b (280 - 315 nm) o o o.
