Lecture_13-2 - The chromophore is responsible for creating...

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Melanocortin-1 Receptor (MC1R) responds to MSH and stimulates cell to produce melanin. Mutation in this gene disrupts melanin coloration. Costs of Melanin production: Melanins are not condition dependent and production of melanin does not require much energy. Perhaps the cost lies in the sacrifice of melanin. Other things melanins do: 1. Antioxidants 2. Cation chelators 3. Tissue strengtheners 4. Antimicrobials and parasite deterrants 5. Photoprotectants 6. Thermoregulators So how might melanin coloration act as a signal of quality to a female? Carotenoid Pigments Many of the red, yellow, and orange coloration seen in the wild (although not all!) Second most prevalent pigments in avian coloration Found in almost all invertebrate phyla and all vertebrate classes Structures are well-described Made up of a chain of carbons containing conjugated double bonds and often have two ring structures at either end.
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Unformatted text preview: The chromophore is responsible for creating light = the chain of conjugated double bonds on the molecule. Light hits the structure, excites electrons so they jump an orbital, and as they come back down, light is emitted. Can change the appearance of the structure. The structure also determines the color produced by the carotenoids. More conjugated double bonds more absorbance of short wavelengths redder color. First place that carotenoids were identified = egg yolks. Animals cannot make carotenoids only plants have the necessary enzyme Must consume plants or prey items that consumed plants Carotenoid deposition and metabolism: Carotenoids ingested absorbed into the liver as micelles metabolized in liver (may change form) pass into circulation and incorporated into lipoproteins deposited into many body tissues (including skin and feathers)...
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This note was uploaded on 04/08/2011 for the course POUL 3123 taught by Professor Navara during the Spring '09 term at University of Georgia Athens.

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Lecture_13-2 - The chromophore is responsible for creating...

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