Relationship between wavelength and energy content of a photon: high wavelength = low energy ie. microwave, infrared (ir) Low wavelength = high energy ie. gamma rays, x-rays. Molecular characteristic of pigments that make them able to absorb light: pigment have a conjugated bond system alternating single and double bonds, non-bonding pi electrons interact with light photons. Relationship between pigments and associated protein: pigments do not just float around, they are attached to proteins. Four fates of the excited state of chlorophyll resulting from absorption of photons: heat, fluorescence longer wavelength, photochemistry change the structure of a pigment molecule, energy transfer.