The protein opsin and the molecule retinal combine to form the pigment found in rods called .

The protein opsin and the molecule retinal combine to form the pigment found in rods called rhodopsin. Rhodopsin is crucial for the process of vision in low-light conditions, as it is sensitive to light and initiates the phototransduction cascade when photons are absorbed. This complex enables the photoreceptor cells (rods) in the retina to detect light, allowing us to see in dim environments. Rhodopsin's structure consists of a protein chain and the chromophore retinal, which undergoes a conformational change upon light absorption, leading to a series of biochemical reactions that ultimately generate visual signals for the brain.