Chapter17 part4 p.581-586

Question 0

Photons of _____ carry the least energy and have the _______ wavelength

Answer 0

red, longest

Question 1

Our eyes are sensitive to wavelengths of

Answer 1

400-700nm

Question 2

photons from __________ contains the most energy and have the ______ wavelength

Answer 2

violet, shortest

Question 3

Both rods and cones contain special organic compounds called

Answer 3

visual pigments

Question 4

pigments are located in each photoreceptor?s __________ segment, in flattened membranous plates called _________

Answer 4

outer, discs

Question 5

Detection of light is called

Answer 5

photoreception

Question 6

First step of photoreception

Answer 6

absorption of photons by visual pigment

Question 7

visual pigments are derivateives of + what is it

Answer 7

rhodopsin- visual purple- visual pigment found in rods

Question 8

rhodopsin conssits of a protein ______ bound to pigment _____ or _______, synthesized from ____________

Answer 8

opsin, retinal, retinene, vitaminA

Question 9

All rods contain the ________ form of opsin

Answer 9

same

Question 10

Describe the retinal pigment of cones

Answer 10

same retinal pigments as rods but retinal is attached to different forms of opsin

Question 11

EAch type of cones have different form of ______

Answer 11

opsin

Question 12

Cone population percentage of each cones

Answer 12

16% blue. 10% green, 74% red

Question 13

New discs w/ visual pigments are continuously assembled at the base of the _________

Answer 13

outer segment of rods/cones

Question 14

completed disc moves to

Answer 14

tip of outer segment

Question 15

After about 10 days, the disc is shed in what

Answer 15

small droplet of cytoplasm

Question 16

what cells absorb droplets with shed discs + what do they do?

Answer 16

pigment cells, they break down the disc membrane’s components and reconvert the retinal to vitaminA. The cells store vitaminA for later transfer to the photoreceptors

Question 17

rhodopsin is broken down through

Answer 17

bleaching

Question 18

Before retinal can recombine w/ opsin, it must be enzymatically converted from _________ form to ________ form

Answer 18

11-trans, 11-cis

Question 19

The retinal conversion takes

Answer 19

energy/ATP, time

Question 20

During bleaching, opsin is ___________ and _________ of cGMP ______

Answer 20

inactivated, breakdown, halts

Question 21

When cGMP breakdown halts, how caan the Na gated channels reopen?

Answer 21

other enzymes in cytoplasm generate cGMP

Question 22

body contains vitaminA reserve for __________

Answer 22

several months

Question 23

Where is one reserve for vitaminA

Answer 23

pigmented part of retina

Question 24

nyctalopia

Answer 24

night blindness- vitaminA deficiency

Question 25

sodium entry through gated channels produce _______ (rods)

Answer 25

dark current

Question 26

In the ________ of cGMP, Na channels are kept open

Answer 26

presence

Question 27

cGMP is a derivative of

Answer 27

GTP

Question 28

When the Na channels are open, the membrane potential is ______ whe the resting membrane potential is ________

Answer 28

-40mV, -70mV

Question 29

When Na channels are open, the photoreceptor is continuously releasing __________ , specifically __________ . The inner segment continuously pumps _______ out

Answer 29

neurotransmitter, glutamate, Na ions

Question 30

Normally, the retinal molecule is in the what form

Answer 30

curved 11-cis

Question 31

when absorbing light, the retinal molecule changes into

Answer 31

more linear 11-trans form

Question 32

the activated 11-trans opsin activated what + describe it

Answer 32

transducin- G protein

Question 33

activated transducin activates what and describe its function

Answer 33

phosphodiesterase (PDE)- breaks down cGMP

Question 34

when dark current is reduced, what happens in terms of neurotramsmitter

Answer 34

rate of neurotransmitter release declines

Question 35

In active state of rod in light, what happens to Na ions?

Answer 35

active transport= export Na from cytoplasm

Question 36

rod active state @ light what happens to membrane potential

Answer 36

drops toward -70mV, hyperpolarization