opsin
Definition
Noun: 1. A light-sensitive protein: Opsin is a type of protein found in the retina of the eye. It combines with a molecule called retinal to form visual pigments like rhodopsin. When light hits these pigments, the opsin changes shape, starting the process that leads to vision.
Usage Examples
- The scientist studied how different opsin proteins respond to various wavelengths of light.
- Mutations in the gene that produces opsin can cause color blindness.
- Rhodopsin is composed of opsin and a chromophore.
Advanced Usage
- Cone opsin vs. rod opsin: Opsins are categorized based on the type of photoreceptor cell they are in. Cone opsins are responsible for color vision in bright light, while rod opsin (found in rhodopsin) is for vision in dim light.
- Evolution of opsins: The study of opsin genes helps scientists understand the evolution of vision in different animals.
Variants and Related Words
- Rhodopsin (n): Often called "visual purple," it is the primary pigment in rod cells, formed by opsin and retinal.
- Photopsin (n): The type of opsin protein found in the cone cells of the retina.
- Chromophore (n): The light-absorbing part of a pigment molecule, such as retinal, which binds to opsin.
Synonyms
- Visual protein
- Photoreceptor protein
Related Terms and Concepts
- Retinal (n): The light-absorbing molecule derived from vitamin A that binds to opsin.
- Phototransduction (n): The biochemical process by which a photon of light triggers an electrical signal in the retina, initiated by the change in opsin.
- G-protein-coupled receptor (GPCR): Opsin is a member of this large family of receptor proteins, which transmit signals into cells.
Noun
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retinal protein formed by the action of light on rhodopsin
