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4.3 outline the role of rhodopsins in rods
outline the role of rhodopsins in rods
- Rhodopsins are light-sensitive pigments, which consist of two molecules bonded together, opsin and retinal. When light enters a rod cell, it splits rhodopsin molecules into its two components. This reaction results in an impulse in the neurone attached to the rod or cone. The two products slowly recombine, ready to be split again by more light. This is known as the visual cycle.
- Rods contain rhodopsin that is sensitive to blue–green light. The figure below shows that this molecule has maximum absorbency at a wavelength of 498 nm, which corresponds to the light of a blue-green colour.