Sensing colour

Question 1

Rods sense

Answer 1

light

Question 2

Cones sense

Answer 2

colour and light

Question 3

What are the 3 types of cone cells

Answer 3

short, medium and long wavelength

Question 4

What cones cells would yellow activate?

Answer 4

red (620nm) and green (550nm)

Question 5

What is a secondary colour

Answer 5

mixing of primary colour

Question 6

What is the photoreceptor molecule in rods?

Answer 6

rhodopsin

Question 7

Opsins are

Answer 7

G-protein coupled receptors (GPCR)

Question 8

what do GPCR do?

Answer 8

signal transduction

Question 9

How does absorption of light generate a signal?

Answer 9

isomerization of the 11-cis-retinal group of rhodopsin to its all-trans form

Question 10

GPCR are attached to what molecule?

Answer 10

trimeric G-protein

Question 11

The trimeric G-protein breaks apart and bit of it interact with proteins. These interactions activate or inhibits these proteins (PDE), changing the level of secondary messengers cGMP. These changes result in what type of response?

Answer 11

Physiological response.

Question 12

Decreases in cGMP changes concentration of … and … ion by opening/ closing protein channels.

Answer 12

Ca+2 and Na+

Question 13

different conc. of ions effect the … that get transmitted via nerve cells (neurones) to the brain where they are processed.

Answer 13

electrical signals

Question 14

What causes colour blindness

Answer 14

defects in colour vision genes which results in either; defects in colour mixing (anomalous trichromacy), or Dichromacy (1 functional cone), monochromic (2 functional cones)

Question 15

How many cone cells does a super colour sensor have?

Answer 15

4, one of which is mutant