12 Photoreceptors & Rhodopsins Flashcards Preview

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Flashcards in 12 Photoreceptors & Rhodopsins Deck (17):
1

During bio-chemical cascade - what molecules are activated by rhodopsin?

G protein molecules

2

During the photoreceptor function sequence, what stage occurs when the photon is absorbed by the chromophore? (Slide 2)

Photoactivation

3

How many discs are in one rod cell? (Slide 3)

1000 discs

4

True or false: all mammals use chromophore as their visual pigment. (Slide 4)

False, all mammals use rhodopsin as their visual pigment.

5

What determines the number of channels that open during the biochemical cascade? (Slide 6)

cG concentration

6

Which process in the bio-chemical cascade closes Na channels? (Slide 10)

PDE breaking down cG to GMP by decreasing cG levels

7

How long does the biochemical cascade last in rods and cones? (Slide 11)

200ms/rods and 100ms/cones

8

True or FalseElectrotonic spread redistributes Na and depolarizes the cell. (Slide 13)

False

9

True or FalseSynaptic deactivation occurs when Ca channels are opened and glutamate release decreases. (Slide 14)

False

10

In a rod, where do the light sensitive molecules reside? (Slide 3)

discs

11

In a cone, where do the light sensitive molecules reside (Slide 3)

membrane

12

What has to occur to change the tail structure of 11-cis retinal from bent to straight? (Slide 4)

photon being absorbed by 11-cis retinal

13

In the dark, about ______ channels open at any one time in each outer segment. (Slide 6)

10,000

14

True or false: Rods can't respond to longer wavelength and respond slower than cones. (Slide 18)

True

15

How many coils you can find in Rhodopsin model? (Slide 22)

Seven coils

16

Where can you find chromophore in Rhodospin molecule? (Slide 23)

Located between six and seven coil

17

What are critical for determining the sensitivity of Chromophore? (Slide 24)

Amino Acids