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23 Cards in this Set
- Front
- Back
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retinal is a
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light absorbing molecule
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retinal is made from
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vitamin a
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retinal combines with proteins called ____ to form 4 types of ____ pigments
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opsin - visual
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when bound to opsin, retinal is
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bent
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when light strikes retinal it causes the molecule to
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straighten and release opsin
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a series of reactions result in electrical impulses down the ____ ____
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optic nerve
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visual pigment in rods is
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rhodopsin (retina + a form of opsin)
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rhodopsin is stored in ____ in ____ ____ of rods
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discs - outer segments
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excitation of rods 3 details
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light strikes rhodopsin - retinal changes shape - releases opsin
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triggers a reaction that initiates an ____
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impulse
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retinal is converted back to its original form in the ____ layer of the retina
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pigmented
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rhodopsin is reformed when the
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retinal attaches to opsin again
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how many types of cones
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3
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each type of cone contains a
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pigment with a different opsin
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in cones, each pigment is sensitive to a different
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wavelength of light
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in cones, each pigment detects a different ____ of light
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color (red, green+ blue)
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breakdown & regeneration of visual pigments in the cones is the same as for ____
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rhodopsin
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in cones, the threshold for activation is much ____ so they respond to ____ ____
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much higher - intense light
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nyctalopia aka
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night blindness
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nyctalopia is caused by
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impairment of rod function
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nyctalopia is most commonly caused by
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vitamin a deficiency
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color blindness is due to lack of
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1 or more cone types at birth
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what is the most common color blindness
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red + green
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