The specific wavelength of light that activates a given photoreceptor can be thought of as analogous to the 3-dimensional shape of a hormonal ligand, and the quantal energy of that wavelength similar to the molar concentration of a hormonal ligand
The specific wavelength of light that activatesa given photoreceptor can be thought of as analogousto the 3-dimensional shape of a hormonal ligand, and the quantal energy of that wavelength similar to themolar concentration of a hormonal ligand