Cone cells, color vision

Light-absorbing pigments differentiate rod cells for black-white vision and three types of cone cells for color vision 807... 

Two types of photoreceptor cell are found in the human retina—rods and cones. Rods are sensitive to low levels of light, while the cones are responsible for color vision at higher light intensities. 

Any one cone cell contains only one type of opsin and is sensitive to only one color of light. Color blindness results from loss or mutation of one or the other of the cone opsins. The combination of 11-c/s-retinaldehyde with cone opsin is sometimes called iodopsin, with rhodopsin meaning more specifically the holo-protein of rod opsin. Most studies of the mechanisms of vision shown in Figure 2.5 have been performed using rods by extrapolation, it is assumed that the same mechanisms are involved in cone vision. 

The human retina contains two types of photoreceptors, rods and cones, that are the primary recipients of visual stimulation. Cones are Involved In color vision, while rods are stimulated by weak light like moonlight over a range of wavelengths. The photoreceptors synapse on layer upon layer of Interneurons that are Innervated by different combinations of photoreceptor cells. All these signals are processed and Interpreted by the part of the brain called the visual cortex. 

The retina of the eye contains cone cells and rod cells. The cone cells are responsible for color vision and for vision in bright light. The rod cells are responsible for vision in dim light. In rod cells, vitamin A is oxidized to an aldehyde and the trans double bond at C-11 is isomerized to a cis double bond. The mechanism for the enzyme-catalyzed interconversion of cis and trans double bonds is discussed in Section 18.15. The protein opsin uses a lysine side chain (Lys 216) to form an imine with (llZ)-retinal, resulting in a complex known as rhodopsin. When rhodopsin... 

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