Chapter 10 Pt. 2 (Part 2) Flashcards
what NT is released by photoreceptors?
glutamate
what NT is released by horizontal cells?
GABA
what NT is released by amacrine cells?
GABA and acetylcholine
secrete GABA
horizontal cells, amacrine cells
secrete glutamate
photoreceptors
where is rhodopsin found?
only in rods
what are the component parts of rhodopsin?
opsin + retinal
what is opsin?
a protein which forms part of the visual pigment rhodopsin
each cone has either…
S, M, or L-opsin
what happens to a retinal structure when it absorbs light?
converts from 11-cis to all-trans
what prompts a retinal structure to convert from 11-cis to all-trans
retinal structure absorbs light
what happens when the retinal undergoes a conformational change?
changes the shape of the opsin protein
what happens when the opsin protein changes shape?
creates a binding site for the trimeric G protein, transducin
what is transducin?
trimeric G protein
what is the role of trimeric G protein transducin when it binds to opsin?
releases GDP and binds GTP
describe what happens to the a-subunit of transducin when GTP binds to transducin
a-subunit of transducin becomes activated and dissociates when GTP binds to transducin
what is the role of the a-subunit ?
the released a-subunit can now bind to and activate cGMP phosphodiesterase
what is the role of cGMP phosphodiesterase?
degrade cGMP to GMP
what wavelength of light has the least energy?
red. longest wavelength.
what wavelength of light has the most energy?
violet. shortest wavelength.
