Lecture 20- Retina and photoreceptors copy

Lecture 20- Retina and photoreceptors copy - 250 Na...

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rods blue cones green cones red cones
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Green Cones contains opsin most senstive to 531 nm Rods contains rhodopsin most senstive to 496 nm Blue Cones contains opsin most senstive 419 nm Red Cones contains opsin most senstive 559 nm
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cones rods
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light light
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Blind spot- region where photoreceptors are NOT present
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cGMP 5’GMP Ligand that binds to Na+ channels Does NOT bind to Na+ channels Phosphodiesterase
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Light One rhodopsin molecule absorbs one photon 500 transducin molecules are excited 100,000 cyclic GMP molecules are hydrolyzed One million Na+ ions per second are prevented from entering the cell 500 phosphodiesterase molecules are excited
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Unformatted text preview: 250 Na channels close + + Residue 296 is the attachment site for retinal. 11-cis retinal All-trans retinal All-trans retinal Active site on opsin is exposed The active site activates transducin and changes rod membrane potential Active site Metabolic energy 11-cis retinal rhodopsin Active site Retinal separates from opsin thereby bleaching rhodopsin Metabolic energy brings opsin back to its original form and attaches retinal to it. Light Absorbtion of light converts 11-cis retinal into all-trans retinal Bipolar cells horizontal cells Ganglion cells...
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This note was uploaded on 10/25/2010 for the course BIO 365R taught by Professor Draper during the Spring '08 term at University of Texas.

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Lecture 20- Retina and photoreceptors copy - 250 Na...

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