Photopsins are light-sensitive proteins found in the photoreceptor cells of the retina, specifically in the cones. They play a crucial role in color vision by absorbing light and initiating the process of visual signal transduction. There are three types of photopsins, each sensitive to different wavelengths of light, allowing humans to perceive a wide range of colors. These proteins work by changing shape when they absorb photons, which triggers a biochemical cascade that ultimately sends signals to the brain. This process enables the brain to interpret visual information, contributing to our ability to see and distinguish colors in our environment.