There are 3 different cone receptors.
In most vertebrates that have what humans term “colour vision”, there appear to be three classes of cones, based on their absorption spectra. Although many fundamental aspects of colour vision remain to be worked out, the chemistry of the cones’ visual pigments is pretty much the same as in the rods. A photon is absorbed by a cis-11-retinal, converting it to the trans-configuration and initiating the phototransduction process.
One of the most important differences between cones and rods is in the amino acid sequence of the opsin component of the rhodopsin molecule. The cones in the three classes of vertebrate cones differ in their absorption spectra because the amino acid sequence of their opsin molecules (opsin is the protein component of rhodopsin, the visual pigment that actually absorbs photons) differs.
In humans, the three classes of cones show maximal absorption efficiency at wavelengths (max) of 420 nm (blue cones), 530 nm (green cones) and 560 nm (red cones).
Learn more about cones here: brainly.com/question/1874359
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