Vision

Question 1

What is the organization of rods and cones in the retina?

Answer 1

cones are more concentrated at the center of the fovea and less in the retina
rods are more concentrated in the retina and less in the fovea

Question 2

Cones

Answer 2

sensitive to sense color and have better resolution and acuity

Question 3

Rods

Answer 3

do not perceive color, higher sensitivity but low acuity can sense lower levels of photons

Question 4

Rhodopsin

Answer 4

combination of opsin and retinol
ROD cell-specific light-sensitive GPCR

Question 5

Meta-rhodopsin

Answer 5

activated rhodopsin
initiates the visual phototransduction second messenger pathway by stimulating the G-protein transducin (Gt), resulting in the liberation of its α subunit.

Question 6

Opsin (GPCR)

Answer 6

a G Protein Coupled Receptor
covalently bound to retinal

Question 7

Activated opsin

Answer 7

when 11-cis-retinal absorbs a photon of light and isomerizes to all-trans-retinal

Question 8

Retinal (cis and trans)

Answer 8

cis: necessary for rhodopsin function
trans: intracellular transport of retinol

Question 9

Transducin

Answer 9

Alpha subunit that is specific for the rod cells

Question 10

‘dark current’

Answer 10

the inward flow of sodium ions into the photoreceptor while an individual is in darkness

Question 11

What is post-binding sensitivity

Question 12

How is the activity of rhodopsin is fine tuned/inhibited
mono-, di-, tri-phosphory; arrestin

Answer 12

mono-, di-, tri-phosphory; arrestin

Question 13

How is the sensitivity to light modified
segregation/redistribution of transducin

Answer 13

segregation/redistribution of transducin

Question 14

What is the progression k

Answer 14

A. open probability of voltage-gated Ca2+ channels
B. membrane depolarization (from approximately -60 mV to -30 mV)
C. all of the above